T  E 


LIBRARY 

OF  THE 

UNIVERSITY  OF  CALIFORNIA. 


Accessions  No 


Bfiek  for  Street  Pavements. 


AN  ACCOUNT  OF  TESTS  MADE  OF  BRICKS  AND  PAVING 
BLOCKS,  WITH  A  BRIEF  DISCUSSION  OF  STREET 
PAVEMENTS  AND  THE  METHOD  OF  CON- 
STRUCTING THEM. 


NEW  EDITION, 


WITH  A  PAPER  ON 


Prepared  for  the  Engineers'  Club  of  Cincinnati,  April,  1894. 


33Y 


.    D.    BURKE,   C.  E. 


CONTENTS. 


The  Samples  Submitted  for  Testing 5 

How  the  Specimens  were  Prepared 7 

Description  of  Specimens  Submitted 9 

How  the  Tests  were  Made 14 

Abrasion  and  Impact 16,  42 

Description  of  the  Tables. 27 

The  Chemistry  of  Brick  Manufacturing , 36 

Discussion  of  the  Tests. , 38 

The  Absorption  Tests 40 

Transverse  Strength 41 

Statistics  of  Traffic  and  Durability  of  Pavements 43 

The  Probable  Durability  of  a  Brick  Pavement » . . .  47 

Municipal  Methods 48 

General  Discussion  of  Pavements 53 

What  Shall  be  Specified 61 

What  Has  Been  Done 68 

Tfte  Matrix 76 

Where  Should  Brick  be  Used  for  Street  Pavements 78 

Maintenance 81 

What  is  in  a  Name. 83 

Size  of  Paving  Brick, 84 

Country  Roads 87 


Brick  for  Street  Pavements. 


AN  ACCOUNT  OF  TESTS  MADE  OF  BRICKS  AND  PAVING 
BLOCKS,  WITH  A  BRIEF  DISCUSSION  OF  STREET 
PAVEMENTS  AND  THE  METHOD  OF  CON- 
STRUCTING  THEM. 


NEW    EDITION, 


WITH    A    PAPER    ON 


COUNTRY    ROADS, 


PREPARED    FOR 


THE   ENGINEERS'  CLUB   OF   CINCINNATI,  APRIL,  1894. 


BY 

M.   D.  BURKE,  C.E. 


THE 

i" 


&SUO& 


CINCINNATI: 

ROBERT    CLARKE    &    CO. 
1894. 


/ 


COPYRIGHTED,  1892. 
BY  ROBERT  CLARKE  &  CO. 


A  large  part  of  the  contents  of  this  pamphlet  was  con- 
tained in  a  report  made  to  the  village  authorities  of  tests  of 
material  to  be  used  in  paving  streets  in  Avondale,  where  the 
writer  was  employed  as  village  engineer.  The  investiga- 
tion then  made  was  as  thorough  as  the  time  and  means  at 
hand  would  justify.  Inquiries  for  the  results  of  the  work 

f\      -         -^ 

have  been  so  numerous,  and  requests  for  the  same  have  b.een 
so  frequently  repeated,  that  it  has  been  deemed  advisable  to 
publish  the  work  in  this  form. 

If  any  information  or  suggestions  herein  contained  shall 
aid  in  the  construction  of  better  pavements,  or  prevent  the 
waste  of  money  upon  bad  ones,  or  shall  bring  people  to  a 
consideration  of  placing  municipal  improvements  under  sys- 
tematic control  and  direction,  or  shall  cause  manufacturers 
to  see  that  their  true  interest  will  best  be  subserved  by  plac- 
ing only  good  material  upon  the  market,  then  this  little 
pamphlet  will  have  served  a  useful  purpose. 

M.  D.  BURKE. 

CINCINNATI,  March  16,  1892. 


BRICK  FOR  STREET  PAVEMENTS. 


THE  SAMPLES  SUBMITTED  FOR  TESTING. 
It  having  been  decided  that  the  Main  Avenue  pavement 
"should  be  constructed  of  some  form  of  clay  product,  a  series 
of  tests  of  the  various  materials  in  market  was  deemed  ad- 
visable in  order  to  aid  in  selecting  the  proper  variety,  and,  if 
found  practicable,  fix  a  standard  by  which  the  different  va- 
rieties might  be  adjudged  and  accepted  or  rejected,  as  their 
qualities  and  powers  of  resistance  would  determine.  Ac- 
cordingly a  circular  letter  was  addressed  to  manufacturers 
and  dealers,  requesting  them  to  ship  to  my  office,  at  41  Pike 
Building,  Cincinnati,  Ohio,  samples  consisting  of  twenty  or 
more  of  each  of  the  varieties  of  the  bricks  or  blocks  manu- 
factured or  sold  by  them  for  street  paving  purposes,  to  be 
tested.  In  response  to  the  circular  letter,  samples  were 
kindly  furnished  by  the  following  parties,  and  numbered  as 
below  : 

1.  Lithonia   Georgia  Granite,  John  Regan,  contractor, 
city. 

2.  West  Virginia  Brick  Co.,  Charleston,  W.  Va.,  H.  C. 
Bruce,  President. 

3.  The   Diamond   Brick   and  Terra  Cotta  Co.,  Kansas 
City,  Mo. 

4.  The  Pittsburg  Sewer  Pipe  and  Fire  Clay  Co.,  New 
Brighton,  Pa. 

5.  Canton  Brick  Co.  (red  granite  street  pavers),  Canton, 

Ohio. 

(5) 


BRICK    FOR    STREET    PAVEMENTS. 

6.  The  Royal  Brick  Co.  (iron  rock  pavers),  Canton,  0. 

7.  Purington  Paving  Brick  Co.,  Galesburg,  111. 

8.  The  United  States  Fire  Clay  Co.,  New  Lisbon,  Ohio  ; 
M.  R.  Coney,  agent. 

9.  The  Middleport  Granite  Brick  Co.  (Hallwood  Block), 
Middleport,  Ohio. 

10.  L.  B.  Townsend  &  Co.  (Townsend  Paver),  Zanesville, 
Ohio. 

11.  The   Brazil  Paving  Block,  Brazil,  Ind.,  L.   H.  Mc- 
Cammon  Bros.,  agents. 

12.  The   Jones   Paving   Block,  Zanesville,   Ohio,  L.  II. 
McCammon  Bros.,  agents. 

13.  The  Ohio  Paving  Co.  (Hallwood  Block),  Columbus, 
Ohio. 

14.  The  John  Porter  Co.,  New  Cumberland,  W.  Va. 

15.  The  New  York  Paving  Brick  Co.,  Syracuse,  N.  Y. 

16.  Hallwood   Block    Granite  Brick,   manufactured  by 
Tennessee  Paving  Brick  Co.,  Robbins,  Tenn. 

In  this  report  the  varieties  are  represented  by  the  numbers 
above  given,  and  the  separate  specimens  by  letters.  Of  each 
variety,  except  Nos.  1  and  16,  ten  bricks  or  blocks  were  used 
in  making  the  various  tests.  A  number  always  indicates  the 
same  variety,  but  only  when  the  number  and  letter  are  the 
same,  does  it  mean  the  same  brick.  Thus  No.  1  always 
means  a  granite  block,  yet  No.  1  A  and  No.  1  E  are  differ- 
ent blocks,  but  both  Georgia  granite. 

It  was  deemed  advisable  to  ascertain,  first,  the  essential 
chemical  ingredients;  second,  the  ratio  of  absorption  ;  third, 
crushing  strength ;  fourth,  transverse  strength ;  fifth,  the  re- 
sistance to  abrasion  and  impact.  The  Riehle  testing  ma- 
chine of  Messrs.  Otten  &  Westerihoff,  appearing  to  be  the 
most  readily  available,  these  gentlemen  were  employed,  not 
only  to  make  the  crushing  and  transverse  tests,  but  also  to 


BRICK    FOR    STREET    PAVEMENTS.  • 

make  the  chemical  analysis  and  determine  the  specific  grav- 
ity and  ratio  of  absorption  of  the  cubes  which  were  pre- 
pared for  the  crushing  test. 

How  THE  SPECIMENS  WERE  PREPARED. 

The  testing  of  a  single  specimen  of  any  kind  being 
deemed  insufficient,  it  was  determined  that  three  cubes  of 
each  variety  be  prepared  for  ascertaining  the  crushing 
strength.  Accordingly  three  bricks  or  blocks  of  each  va- 
riety were  taken  at  random,  and  sent  to  the  marble  works  of 
Joseph  Foster  &  Sons,  placed  in  the  mill  and  sawed  in  two 
lengthwise,  the  cut  being  made  so  as  to  leave  one  piece  about 
2J  inches  in  width.  This  piece  was  then  cut  by  the  saws  trans- 
versely, so  as  to  approximate  as  nearly  as  practicable  to  a 
2-inch  cube  from  the  interior  of  the  brick.  The  roughly 
sawn  cubes  were  then  placed  upon  a  rubbing  bed  and  worn 
down  to  the  required  size,  with  parallel  and  equal  faces. 
Three  such  cubes  were  made  of  each  variety.  Of  the  gran- 
ite, A  and  B  were  made  from  one  block ;  C  from  another. 
Number  16,  the  three  cubes  were  made  from  a  single  block, 
as  of  this  number  but  three  blocks  were  furnished.  In 
making  No.  15,  which  is  of  a  very  refractory  material,  the 
saw  was  unfortunately  deflected  in  such  a  manner  that 
cubes  could  not  be  obtained  from  two  of  the  pieces,  B  and 
C,  and  they  were  rubbed  down  to  two  inches  square  by  1J 
inches  high. 

Subsequent  developments  show  that  it  would  have  been 
advisable  to  have  made  1J  inch  cubes  instead  of  2  inch.  The 
testing  machine  used  has  a  capacity  of  52,000  pounds.  It 
was  thought  that  very  few,  if  any,  of  the  specimens  would 
show  an  ultimate  crushing  strength  exceeding  13,000  pounds 
per  square  inch,  but  in  this  we  were  mistaken. 

By  the   same    process   above   described,  four  "  granite 


BRICK    FOR    STREET    PAVEMENTS. 

bricks"  were  manufactured;  that  is,  four  pieces  of  granite 
2Jx4x8  inches  were  made,  to  be  subjected  to  the  same  tests 
as  the  bricks,  in  order  to  compare  the  resistance  of  the  clay 
products  with  a  standard  paving  material.  It  will  be  ob- 
served that  great  care  Was  taken  in  this  work  in  order  to 
preserve  the  material  of  each  specimen  intact  and  to  pre- 
vent injury  to  it  in  any  way.  No  cutting  with  chisels  or 
spalling  was  permitted.  Each  specimen  was  numbered  and 
lettered  and  its  identity  preserved  throughout  the  entire 
series  of  tests.  The  cubes  were  used  for  three  purposes  : 
First,  for  obtaining  the  ratio  of  absorption  ;  second,  specific 
gravity,  and  third,  the  crushing  strength  of  the  material. 
Another  absorption  test  Was  made  with  whole  bricks,  and 
in  some  instances  the  percentages  obtained  differed  materi- 
ally. There  are  two  reasons  for  these  differences  :  A  single 
cube  only  was  used  and  it  was  immersed  but  twelve  hours. 
For  some  of  this  material  probably  this  length  of  time  was 
too  short  for  it  to  absorb  all  the  water  that  it  would  ulti- 
mately take  up,  but  generally  the  percentages  obtained  by 
immersing  the  cubes  was  materially  higher  than  that  ob- 
tained from  the  whole  bricks,  which  is  a  result  to  be  ex- 
pected when  it  is  remembered  that  the  outer  portions  of 
the  bricks  were  in  several  cases  salt-glazed  and  were  gener- 
ally more  dense  and  burned  harder  than  the  interior  portion 
from  which  the  cubes  were  obtained.  The  specimens  sub- 
jected 'to  crushing  were  lettered  A,  B,  C,  those  lettered  A 
being  used  for  the  absorption  as  well  as  the  crushing  test. 

No  essential  preparation  of  the  specimens  for  the  re- 
maining tests  was  necessary,  They  were  all  kept  in  a  steam- 
heated  room  from  the  time  of  their  arrival  until  used,  which 
was  about  one  week  for  the  latest  arrivals,  and  about  four 
weeks  for  the  earliest.  All  would  be  classed  as  perfectly 
dry.  All  adhering  sand  or  'dust  was  carefully  brushed  from 


BRICK  FOR  STREET  PAVEMENTS. 

those  tested  for  absorption  or  abrasion  before  weighing  them. 
In  selecting  those  used  for  ascertaining  the  transverse 
strength,  perfect  specimens,  showing  no  fire  cracks  or  other 
defects,  were  taken.  In  fact  the  manufacturers  or  agents 
had  generally  done  the  selecting  and  packing  with  such  care 
that  no  outside  defects  were  visible,  except  as  noted  for 
No.  10. 

DESCRIPTION  OF  SPECIMENS  SUBMITTED. 

No.  1.  Application  was  made  to  the  Southern  Granite 
Company  for  specimens  of  their  material,  but  none  was  re- 
ceived, accordingly  the  samples  used  were  obtained  from  Mr. 
John  Regan,  contractor,  who  was  using  Lithonia  granite  in 
paving  a  street,  and  the  cubes  and  specimen  bricks  were 
sawed  from  the  interior  of  the  blocks,  rubbed  down,  with- 
out the  use  of  hammer  or  chisel,  to  the  dimensions  given 
as  above  noted,  in  the  preparation  of  the  specimens. 

No.  2  is  a  hard  burned  brick  manufactured  from  plastic 
clay  and  burned  in  the  ordinary  clamp  kiln.  It  is  about 
2J"x3f"x8",  and  if  closely  laid,  about  sixty-five  of  them 
would  pave  a  square  yard.  Its  record  can  be  traced  through 
the  various  tests  in  the  following  tables  by  its  number.  Its 
history  as  a  street  paver  is  said  to  be  quite  satisfactory  in 
some  localities,  but  it  should  not  be  used  where  the  traffic  is 
very  considerable. 

No.  3  is  manufactured  from  a  shale  or  plastic  clay  which 
readily  vitrifies.  In  size  it  averages  2J''x3f"x8",  and  about 
sixty- eight  will  be  required  for  each  square  yard  of  pave- 
ment. The  chemical  analysis,  as  given  in  table  No.  1,  does 
not  show  that  it  contains  an  objectionable  amount  of  lime, 
but  other  tests  unmistakably  manifest  its  presence  in  form 
and  quantity  to  a  highly  detrimental  degree.  The  brick  is 
very  hard  and  dense,  ranking  third  in  specific  gravity,  but  it 
is  rather  small  and  quite  brittle,  the  fracture  being  con- 


10  BRICK    FOR    STREET    PAVEMENTS. 

-choidal,  and  it  will' yield  to  the  trituration  of  animals'  shoes 
rather  than  the  grinding  of  the  wheels  of  vehicles.  I  have 
no  knowledge  of  its  record  in  actual  service  as  a  street 
paver. 

No.  4  is  what  is  known  as  a  lire-clay  brick.  In  color  it 
is  an  orange  buff.  The  average  size  is  2J"x4J"x8J".  About 
fifty-nine  \vould  lay  a  square  yard  of  pavement.  It  absorbs 
water  rather  freely,  but  not  to  a  greater  extent  than  many 
acceptable  building  stones,  and  in  all  the  other  tests  its  stand- 
ing is  good. 

Nos.  5  and  6  are  practically  the  same  brick,  manufac- 
tured from  a  shale  or  indurated  clay.  In  color  they  are  a  dark 
red.  They  average  2J"x4i"x8f",  and  about  fifty-nine  of 
them  will  pave  a  square  yard.  The  samples  tested  are  all 
burned  quite  hard,  but  not  in  all  cases  to  vitrification  ;  hence 
while  they  show  great  transverse  strength,  and  resist  abra- 
sion well,  they  are  comparatively  low  in  crushing  strength 
and  there  is  great  variation  in  the  percentage  of  absorption. 
Their  record  in  actual  use  is  quite  satisfactory,  but  I  have 
no  statistics  of  the  severity  of  the  traffic  to  which  they  have 
been  subjected. 

No.  7  is  of  a  dark  red  color,  2J"x3f "x7f"  in  size.  About 
sixty-nine  will  be  required  for  each  square  yard  of  pave- 
ment. In  all  the  tests  this  ranks  among  the  best  of  the  red 
bricks,  and  its  record  under  moderate  traffic  is  good.  An 
increase  in  size  so  as  to  afford  a  greater  weight  of  pavement 
would  appear  to  be  prudent  if  it  is  to  be  used  under  heavy 
traffic. 

No..  8  is  a  fire-clay  brick  of  a  light  buff  color,  2T9g"x 
3|£"x8Ty,  of  which  about  fifty -five  will  pave  a  square  yard. 
The  material  of  which  it  is  composed  has  not  been  very 
finely  ground  nor  very  thoroughly  compressed.  As  a  con- 
sequence it  has  a  low  specific  gravity,  a  moderately  high  rate 


BRICK    FOR    STREET    PAVEMENTS.  11 

of  absorption,  and  is  outranked  by  several  other  varieties  in 
the  other  tests,  but  in  the  uniform  quality  of  each  individual 
brick  as  compared  with  the  others  of  its  kind,  it  stands  at 
the  head  of  the  list. 

No.  9.  In  chemical  constituents  this  coincides  more 
nearly  with  No.  2  than  any  of  the  other  samples  submitted, 
yet  the  treatment  of  the  material  has  been  so  different  that 
the  results  are  in  no  respect  similar.  It  is  a  glazed  Ha  11- 
woo'd  block,  21y'x3f"x8J",  and  about  fifty-five  of  them  will 
lay  a  square  yard  of  pavement.  The  glaze  is  said  to  be  a 
natural,  and  not  a  salt  glaze.  The  corners  are  rounded  to 
about  one-half  inch  radius,  and  two  J"  groves  extend  length- 
wise around  the  block  near  its  middle.  The  clay  has  been 
finely  ground  and  completely  vitrified,  but  inasmuch  as  it 
contracts  greatly  in  burning,  the  blocks  are  liable  to  show 
cracks  on  the  outside  or  cavities  on  the  inside.  When 
broken  the  blocks  show  an  even  dense  texture  of  a  dark 
brown  color,  and,  were  the  defect  above  noted  remedied 
(which  it  would  appear  to  the  writer,  could  be  readily  done), 
they  would  be  greatly  improved  for  street  paving  purposes. 

No.  10  had  been  assorted  to  some  extent  when  they  came 
into  my  hands,  as  more  than  one-fourth  of  the  bricks  had 
been  broken  in  the  box.  The  average  size  ?.s  2^'fx±"x8^j", 
and  fifty-eight  of  them  will  lay  a  square  yard  of  pavement. 
They  are  dark  brown  in  color,  with  corners  rounded  to 
about  one-fourth  of  an  inch  radius;  burned  exceedingly 
hard,  although  they  do  not  present  the  melted  appearance 
of  most  of  the  vitrified  bricks.  While  this  brick  has  great 
hardness,  with  sufficient  density  for  all  practical  purposes, 
:and  even  a  high  degree  of  tenacity  under  a  steadily  applied 
stress,  yet  it  possesses  great  brittleness,  and  when  subjected 
to  shocks,  shows  a  tendency  to  spall  badly.  Could  the  qual- 
ity of  toughness  be  given  it  without  materially  diminishing 


12  BRICK    FOR    STREET    PAVEMENTS. 

its  hardness,  no  essential  of  a  desirable  brick  paver  would  be 
lacking. 

No.  11  is  manufactured  from  a  clay  found  in  the  coal 
measures  but  not  termed  a  fire-clay.  It  is  a  salt-glazed 
block  2|"x4"x9J"  in  size,  and  each  square  yard  of  pavement 
will  require  about  forty-eight  blocks.  The  corners  are 
slightly  rounded.  Little  fault  can  be  found  with  the  chem- 
ical ingredients,  although  an  additional  amount  of  iron 
would  be  in  better  proportion  to  the  quantity  of  alkalies 
present.  The  form  and  size  of  block  has  been  well  chosen 
if  such  a  thickness  can  be  properly  burned,  but  the  mechan- 
ical work  of  preparing  the  material  and  forming  the  block 
has  been  indifferently  done  and  the  burning  decidedly  un- 
derdone. 

No.  12,  is  of  well  chosen  dimensions,  being  2f//x4J"x9", 
and  fifty-one  blocks  will  lay  a  square  yard  of  pavement.  The 
material  of  which  it  is  composed  is  about  the  same  as  that  of 
which  No.  10  is  made,  namely,  a  mixture  of  shale  and  clays 
found  in  the  coal  measures.  The  corners  are  rounded  to 
about  one-fourth  of  an  inch  radius.  The  blocks  are  re- 
pressed, with  five  grooves  passing  transversely  nearly  across 
one  side,  and  eight  diagonally  nearly  across  the  other.  The 
sand,  or  possibly  the  oil,  used  in  repressing,  serves  to  give 
it  a  reddish  brown  color.  Giving  the  block  a  form  such 
that  it  should  always  be  placed  with  the  same  side  up  ap- 
pears to  be  a  refinement  hardly  required  in  practice.  The 
material  might  have  been  made  into  a  good  paving  block, 
,but  it  was  not.  The  clays  were  not  ground  sufficiently  fine, 
neither  was  the  burning  carried  to  such  an  extent  as  to  pro- 
duce a  block  that  would  withstand  the  abrasion  of  street 
traffic.  The  samples  tested  were  obtained  from  an  agent, 
and  not  directly  from  the  manufacturers. 

No.  13,  is  salt-glazed,  corners  rounded  to  about  one-half 


BRICK    FOR    STREET    PAVEMENTS.  13 

inch  radius,  with  two  grooves  about  one  and  one-half  inches 
apart,  passing  lengthwise  around  it  near  the  middle.  About 
forty-six  blocks  will  pave  one  square  yard.  It  shows  a 
higher  percentage  of  iron  than  any  other  specimen  analyzed, 
but  appears  to  be  mainly  composed  of  a  plastic  clay,  possi- 
bly indurated,  which  has  been  finely  ground  and  skillfully 
combined.  In  the  process  of  burning  or  vitrification,  the 
iron  and  alkalies  have  combined  so  as  to  render  the  material 
practically  impervious  to  moisture,  but  it  has  not  quite  as  high 
a  specific  gravity  nor  the  strength  that  should  be  obtained 
with  this  material.  Its  record -in  practical  use  is  very  good, 
and  under  any  thing  like  fair  treatment  will  give  satisfactory 
results. 

No.  14,  is  a  repressed  fire-clay  brick,  with  corners 
rounded  to  about  three-sixteenths  of  an  inch  radius.  The 
average  size  is  2J//x4J//x8J",  and  sixty  of  them  will  pave 
a  square  yard.  The  material  is  very  similar  to  No.  4,  but 
the  repressing  has  given  it  advantages  in  some  particulars. 
It  is  of  a  buff  color.  It  has  been  used  as  extensively  for 
street  paving  as  any  other  variety  tested,  and  under  mod- 
erate traffic  its  record  has  been  satisfactory.  A  result  ap- 
pears to  be  attainable  with  this  material  which  is  not  al- 
ways secured,  but  when  it  is,  leaves  but  slight  room  for  ap- 
parent improvement  in  the  manufacture  of  paving  blocks. 
It  is  obtained  by  the  fusion  of  the  iron  with  the  silica  when 
acted  upon  by  the  alkalies  or  other  fluxes,  in  the  pro- 
cess of  burning  or  vitrification,  producing  a  block,  which, 
when  broken,  presents  a  gray  metallic  or  granitic  texture, 
showing  no  traces  of  cleavage  or  granular  structure,  and 
perfectly  uniform  throughout.  Of  the  sample  bricks  of  this 
variety  tested,  about  seventy-five  per  cent  were  completely 
vitrified  as  here  described,  while  the  others  presented  a 
granular  appearance,  either  throughout  or  in  the  central  por- 

OF  THS 

'n    ". 


14  BRICK    FOR    STREET    PAVEMENTS. 

tion,  but  they  were  all  very  hard  burned.  The  cube  used 
for  obtaining  specific  gravity  and  percentage  of  absorption 
was  but  partially  fused,  hence  it  shows  great  affinity  for 
moisture.  This  fusion  does  not  appear  to  add  materially  to 
the  strength,  but  it  does  lessen  the  amount  of  absorption 
without  materially  increasing  the  brittleness. 

No.  15,  is  drab  or  brown  in  color,  2J/rx3Ty/x7|/r  in 
size,  requiring  about  seventy-five  of  them  to  lay  a  square 
yard  of  pavement.  The  clay  from  which  this  brick  is  made 
is  evidently  largely  formed  from  the  disintegration  of  lime- 
stone rocks.  All  the  samples  were  thoroughly  vitrified,  and 
the  product  is  an  exceedingly  refractory  substance.  Could 
the  lime  be  eliminated  from  it  before  burning,  the  bricks 
would  be  as  nearly  indestructible  as  could  be  desired,  but 
every  brick  tested  manifested  the  presence  of  lime  in  quan- 
tity sufficient  to  impair  its  durability. 

No.  16,  is  made  from  a  shale  or  clay  found  in  the  coal 
measures,  although  not  described  as  a  fire  clay.  But  three 
of  these  blocks  were  obtained  for  making  the  tests,  and 
each  was  quite  a  perfect  specimen  of  its  kind.  This  is  a 
Hallwood  block,  corresponding  in  dimensions  with  No.  13, 
and  if  the  samples  fairly  represent  the  product  of  the  kilns, 
pavements  properly  laid  with  this  material  will  be  both  dura- 
ble and  satisfactory. 

How  THE  TESTS  WERE  MADE. 

Absorption. — Of  the  cubes  prepared  as  before  described, 
the  one  lettered  "A"  of  each  variety  was  placed  in  a  drying 
oven  and  maintained  at  a  temperature  of  212°  Fahrenheit 
for  twelve  hours,  in  order  to  drive  off  any  contained  mois- 
ture. Each  was  then  accurately  weighed.  The  figures  ob- 
tained are  found  in  the  second  column  from  the  left  of 
Table  No.  2.  It  was  then  immersed  in  water,  where  it  re- 


BRICK    FOR    STREET    PAVKMEMS.  15- 

mained  for  the  succeeding  twelve  hours,  when  it  was  taken 
out,  the  adhering  moisture  wiped  off,  and  again  weighed,  the 
results  heing  noted  in  the  third  column  from  the  left  in  the 
same  table.  At  this  time  it  was  also  weighed  in  water,  these 
last  weights  being  found  in  the  sixth  column  of  Table 
No.  2. 

For  a  further  test  of  absorption  two  whole  bricks  of  each 
variety  (except  as  noted  in  the  table)  were  selected  at  ran- 
dom, lettered  G  and  H  respectively,  placed  on  an  ordinary 
counter  scale  weighing  to  quarter  ounces,  the  results  noted, 
and  are  found  in  the  ninth  column  from  the  left  in  table 
No.  2.  They  were  then  placed  in  water  and  kept  entirely 
submerged  for  seventy  hours,  when  they  were  taken  out, 
dried  with  a  towel,  again  weighed,  with  results  found  in  the 
tenth  column  of  the  same  table.  These  results  are  only  as 
accurate  as  the  scales  were,  but  the  test  can  be  readily  re- 
peated at  any  time,  and  will  give  a  fair  practical  measure  of 
the  absorption  to  be  expected  from  whole  bricks  in  a  sim- 
ilar length  of  time.  The  samples  had  been  kept  in  a  steam- 
heated  room  during  the  preceding  ten  days,  and  the  dust  and 
sand  were  carefully  brushed  from  them  before  the  first 
weighing. 

Crushing  Strength. — For  determining  the  crushing 
strength  the  cubes  were  carefully  measured, 'their  upper  and 
lower  surfaces  protected  by  a  thickness  of  blotting  papery 
and  they  were  subjected  to  pressure  in  a  Riehle  Testing  Ma- 
chine of  52,000  pounds  capacity.  The  results  obtained  will 
be  found  in  table  No.  3.  No  visible  effect  was  produced 
upon  the  granite  except  that  "  B"  was  very  slightly  spalled, 
as  noted.  No.  15  "  C,"  which  was  about  one  and  one-half 
by  two  inches,  was  set  on  edge  after  being  tried  the  other 
way,  and  a  pressure  exerted  exceeding  17,000  pounds  per 


16  BRICK    FOR    STREET    PAVEMENTS. 

square  inch,  but  it  could  not  be  crushed,  although  it  spalled 
at  one  corner  at  a  little  over  7,000  pounds  per  square  inch. 

Transverse  Strength. — The  transverse  strength  was  as- 
certained in  the  same  machine  in  the  following  manner  : 
Three  bricks  of  each  variety  (except  as  noted)  were  chosen 
and  lettered  D,  E  and  F.  The  lower  knife  edges  were  ad- 
justed at  precisely  six  inches  apart,  the  upper  knife  edge 
being  placed  centrally  between  them.  Each  specimen  was 
carefully  measured  and  its  surface  protected  from  direct 
abrasion  at  the  points  of  bearing  by  two  or  three  thick- 
nesses of  blotting-paper,  and  the  weight  required  to  break 
it  carefully  noted.  These  results  are  found  in  table  No.  4. 

ABRASION  AND  IMPACT. 

The  method  adopted  for  determining  the  relative  re- 
sistance to  abrasion  and  impact  was  that  which  is  com- 
monly known  as  the  rattling  test.  A  cylinder  about  six 
feet  in'  length  by  twenty-eight  inches  in  diameter,  contain- 
ing pieces  of  cast  iron,  varying  in  weight  from  one  to  six 
or  eight  pounds,  and  in  the  condition  in  which  it  is  ordina- 
rily used  for  cleaning  castings,  was  selected  for  this  purpose. 
Four  bricks  of  each  variety  (with  the  exceptions  noted  in  the 
table)  were  selected  and  lettered  G,  II,  I  and  J,  two  of  the 
specimens,  G  and  H,  having  been  soaked  for  the  preceding 
seventy  hours.  The  specimens  were  carefully  weighed  and 
.all  placed  in  the  rattler  at  one  time.  Billets  of  wood  were 
put  in  with  them,  as  is  ordinarily  done  in  cleaning  cast- 
ings, to  prevent  breaking.  The  cylinder  was  revolved  at  a 
speed  of  about  twenty-four  revolutions  per  minute,  and  at 
the  end  of  one  thousand  revolutions  was  stopped,  the  speci- 
mens taken  out,  weighed  and  the  loss  of  each  noted.  The 
object  of  making  this  fl^rst  test  in  this  particular  manner 
was  to  wear  away  the  sharp  angles  or  corners  and  bring 


BRICK  FOR  STREET  PAVEMENTS.  17 

each  piece  as  nearly  as  practicable  on  a  level  footing  with 
its  fellow  for  that  which  was  to  follow.  This  first  test, 
therefore,  was  intended  more  to  equalize  the  several  pieces 
than  to  measure  their  actual  wear. 

On  the  following  day  the  specimens  were  again  placed 
in  the  cleaner,  omitting  the  protecting  billets  of  wood.  The 
object  now  being  to  observe  the  survival  of  the  fittest. 
The  cylinder  was  given  three  thousand  revolutions,  occupy- 
ing something  over  two  hours  in  time,  and  although  all  the 
pieces  were  in  at  the  same  time,  excepting  a  fragment  of  ~No. 
15  "  I,"  which  had  broken  off  in  the  former  test  and  was  in- 
advertently omitted ;  there  was  ample  room  for  .motion  and 
the  loss  in  weight  of  every  piece  was  a  measurable  quantity. 
The  individuality  of  some  specimens  was  lost,  as  the  marks 
were  in  some  cases  almost  entirely  worn  away,  but  there  was 
no  trouble  in  identifying  the  varieties ;  hence,  in  tabulating 
the  results  of  this  work  the  percentage  of  loss  in  the  sec- 
ond rattler  test  is  given  for  each  variety.  This  will  be  found 
in  detail  in  table  !N"o.  5. 

With  the  completion  of  the  second  rattler  test  closed 
the  actual  work  upon  the  specimens,  and  the  labor  of  col- 
lating the  information  obtained  was  commenced.  Further 
investigation  would  appear  to  be  desirable,  especially  some 
test  that  will  more  nearly  resemble  the  attrition  of  the  shoes 
of  animals  in  passing  over  the  pavement  than  do  any  of  the 
tests  that  were  made.  But  the  information  now  gained 
would  appear  to  justify  seeking  that  knowledge  by  a  prac- 
tical test  of  the  brick  in  the  street  pavement  itself. 
2 


18 


BRICK   FOR   STREET   PAVEMENTS. 


TABLE  No.  1.— CHEMICAL  ANALYSES. 


No.  OF  SPEC- 
IMEN. 

SILICA. 

ALUMINA. 

PEROXIDE 
OF  IRON. 

« 
i 

i3 

MAGNESIA. 

ALKALIES. 

UNDETER- 
MINED. 

TOTAL  PER- 
CENTAGES. 

2 

73.32 

14.82 

8.34 

0.70 

0.99 

2.26 

100.43 

3 

64.37 

19.73 

9.07 

0.82 

2.32 

1.89 

1.80 

100.00 

4 

67.36 

22.05 

5.61 

0.86 

0.36 

2.70 

1.06 

100.00 

5 

67.65 

18.36 

8.34 

0.80 

1.02 

2.58 

1.25 

100.00 

6 

68.12 

18.63 

8.53 

0.68 

0.71 

2.58 

0.75 

100.00 

7 

68.69 

17.95 

7.25 

0.76 

1.47 

2.83 

1.05 

100.00 

8 

64.08 

25.32 

5.44 

0.30 

0.29 

0.63 

3.94 

100.00 

9 

71.57 

17.06 

8.34 

0.50 

0.58 

0.56 

1.39 

100.00 

10 

61.80 

20.76 

8.70 

1.38 

1.09 

1.44 

4.83 

100.00 

11 

77.67 

14.77 

3.63 

0.38 

0.27 

2.43 

0.85 

100.00 

12 

65.08 

22.39 

7.97 

0.62 

0.74 

2.33 

0.87 

100.00 

13 

66.30 

18.62 

9.78 

0.40 

0.84 

1.89 

2.17 

100.00 

14 
15 

69.02 
67.67 

22.07 
11.67 

4.53 
6.53 

1.70 
12.74 

0.38 
0.95 

1.34 
0.80 

•  0.96 

100.00 
100  .  36 

16 

70.57 

15.19 

7.97 

0.78 

0.32 

1.15 

4.02 

100.00 

Undertermined  is  water  manganese  oxide  and  possibly  some  titanic  acid. 

OTTEN  &  WESTENHOFF, 

Chemists. 


BRICK  FOR  STREET  PAVEMENTS. 


19 


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20 


BRICK    FOR    STREET    PAVEMENTS. 


TABLE  No.  3.— CRUSHING  STRENGTH. 


SPECIMEN  NO.  || 

|  LETTER. 

SIZE   IN  INC. 

AREA  IN 
|  SQUARE  IN. 

SPALLED  AT 
IN  POUNDS. 

SPALLED  AT  II 
IN  POUNDS 
PER  SQ.  INCH.  || 

CRUSHED  AT 
IN  POUNDS. 

CRUSHED  AT 
IN  POUNDS 
PER  SQ.  INCH. 

REMARKS. 

1 

B 

1 
I 

g 

1 

B 

2. 

2. 

2. 

4. 

40480 

10120 

Did  not  crush  at  52000  lbs.=13000  Ibs. 

2 

A 

1.97 

1.97 

1.94 

3.82 

29600 

7749 

35500 

9293 

per  D". 
Soaked  12  hours. 

2 

B 

1.94 

1  94 

1.94 

3.76 

28000 

7447 

35920 

9553 

2 

C 

1.94 

1.97 

1.94 

3.82 

Did  not  spall  at  52000  Ibs.  =  13613  Ibs. 

3 

A 

1.97 

1.97 

1.97 

3.88 

32290 

8322 

37720 

9722 

per  D". 
Soaked  12  hours. 

B 

1.94 

1.97 

1.94 

3.82 

15200 

3979 

48000 

12565 

3 

C 

1.97 

1.94 

1.94 

3.76 

18100 

4813 

32720 

8702 

4 

A 

1.97 

1.97 

1.97 

3.88 

33110 

8533 

43120 

11113 

Soaked  12  hours. 

4 

B 

1.97 

1.97 

1.97 

3.88 

36590 

9427 

Did  not  crush  at  52000  Ibs.  =  13402  Ibs. 

per  Q". 

4 

C 

1.97 

1.97 

1.97 

3.88 

Did  not  spall  at  52000  Ibs.  =  13402  Ibs. 

5 

A 

1.94 

1.97 

1.94 

3  82 

50000 

13089 

per  D". 

Soaked  12  hours.     Did   not   crush    at 

52000  Ibs.  =  13613  Ibs.  per  Q". 

5 

B 

1.97 

1.97 

1.97 

3.88 

38850 

10013 

39150 

10090 

5 

C 

1.97 

1.97 

1  97 

3.88 

28000 

7216 

38850 

10013 

6 

A 

1.94 

1.91 

1.91 

3.65 

19650 

5383 

23100 

6329 

Soaked  12  hours. 

6 

B 

1.94 

1.94 

1.91 

3.70 

37220 

10059 

51500 

13919 

6 

C 

1.97 

2.00 

1.97 

3  94 

Did  not  spall  at  52000  Ibs.  =  13198  Ibs. 

7 

A 

2.00 

1.97 

1.97 

3.88 

25120 

6471 

51600 

13300 

per  D  • 
Soaked  12  hours. 

7 

B 

1.97 

1.97 

1.97 

3.88 

Did  not  spall  at  52000  Ibs.  =  13402  Ibs. 
per  D''. 

7 

C 

1.97 

1.97 

1.97 

3.88 

38550 

9935 

52000 

13402 

8 

A 

1.97 

1.97 

1.94 

3.82 

34000 

8900 

46460 

12162 

Soaked  12  hours. 

8 

B 

1.97 

1.97 

1.94 

3.82 

25220 

6602 

44650 

11688 

8 

C 

1.97 

1.97 

1.97 

3.88 

25030 

6451 

39570 

10198 

9 

A 

1.97 

1.97 

1  94 

3.82 

24000 

6283 

39820 

10424 

Soaked  12  hours. 

9 

B 

1.97 

2.12 

1  97 

4.18 

26000 

6220 

48270 

11548 

9 

C 

2.00 

1  97 

.94 

3.82 

17500 

4581 

39820 

10424 

10 

A 

1.97 

1  97 

.97 

3.88 

50750 

13080 

Soaked   12  hours.     Did   not  crush  at 

52000  Ibs.  =13402  Ibs.  per  Q". 

10 

B 

.97 

1.97 

97 

3.88 

35500 

9149 

51460 

13263 

10 

C 

.97 

1.97 

.94 

S  82 

32000 

8377 

50050 

13102 

11 

A 

.97 

1.97 

.97 

3.88 

27900 

7191 

50300 

12964 

Soaked  12  hours. 

11 

B 

.97 

1.97 

94 

3.82 

24000 

6283 

39400 

10314 

11 

C 

.97 

1.97 

1.97 

3.88 

23880 

6155 

27250 

7023 

12 

A 

.97 

1.94 

1.94 

3.76 

19700 

5239 

37330 

9928 

Soaked  12  hours. 

12 

B 

.97 

1.97 

1.97 

3.88 

14240 

3670 

17620 

4541 

12 

C 

.00 

1.97 

1.94 

3.82 

10960 

2869 

28110 

7359 

13 

A 

.91 

1.97 

1.97 

3.88 

28000 

7216 

48000 

12371 

Soaked  12  hours. 

13 

B 

.97 

1.97 

1.97 

3.88 

40000 

10309 

46600 

12010 

13 

C 

.94 

1.97 

1.91 

3.76 

19500 

5186 

38380 

10207 

14 

A 

.97 

1.97 

1.97 

3.88 

38800 

10000 

50770 

13085 

Soaked  12  hours. 

14 

B 

1.97 

1.97 

1.97 

3.88 



Did  not  spall  at  52000  Ibs.  =  13402  Ibs. 

per  D  • 

14 

c 

1.97 

1.97 

L  94 

3.82 

Did  not  spall  at  52000  Ibs.  =  13613  Ibs. 

15 

A 

1.97 

1.97 

1.97 

3.88 

27770 

7157 

per  Q. 
Soaked    12  hours.     Did   not  crush  at 

52000  Ibs.  =  13402  Ibs  per  Q". 

15 

B 

1.50 

1.97 

1.97 

3.88 

Did  not  spall  at  52000  Ibs.  =  13402  Ibs. 

15 

C 

1.50 

2.03 

1.94 

3  94 

per  D". 
Did  not  spall  at  52000  Ibs.  =  13198  Ibs. 
per  D  • 

15 

c 

1.94 

2.03 

1.50 

3.04 

35400 

11644 

Did  not  crush  at  52000  Ibs.  =  17105  Ibs. 

16 

A 

2. 

2. 

2. 

4.00 

51660 

12915 

Soaked  12  hours.    Did  not  crush  at  52000 

Ibs.  =  13000  Ibs.  per  D". 

16 

B 

2. 

1.97 

1.97 

3.88 

Did  not  spall  at  52000  Ibs.  =  13402  Ibs. 
per  D". 

16 

C 

2. 

2. 

2. 

4.00 

Did  not  spall  at  52000  Ibs.  =  13000  Ibs. 

per  D  . 

BRICK    FOR    STREET    PAVEMENTS. 


21 


TABLE  No.  4. — TRANSVERSE  STRENGTH. 


SIZE  IN   INCHES. 

SECTIONAL 
AREA  IN 
SQ.  INCHES. 

BREAKING 
WEIGHT  IN 
POUNDS. 

MODULUS  OF 
RUPTURE. 

AVERAGE  OF 
THREE  TESTS. 

REMARKS. 

|        g 

"   s 

M 

1 

M 

1 

R 

R 

..    2.25 

4.19 

6.0 

9.43 

6590 

1501 

Only  one  specimen  broken.    Broke  at 

D    2.31 

3  82 

6.0 

8.82 

4580 

1222 

one  of  the  lower  knife  edges. 

E    2.31 

3.75 

6.0 

8.66 

6500 

1801 

-1444 

F    2.31 

3.875 

6.0 

8.95 

5050 

1310 

D    2.125 

3.625 

6.0 

7.70 

5620 

1811 

E    2.19 

3.625 

6.0 

7.94 

7600 

2377 

-2040 

F    2.125 

3.44 

6.0 

7.31 

5400 

1932 

D    2.50 

4.125 

60 

10  31 

11680 

2472 

E    2.50 

125 

6.0 

10.31 

8000 

1693 

2197 

F    2.50 

.06 

6.0 

10.15 

11110 

2427 

D    2.50 

.94 

6.0 

9  85 

13320 

3089 

E    2.50 

.00 

6.0 

10.00 

11160 

2511 

-2963 

F    2  44 

.125 

6.0 

10  06 

15170 

3288 

D    2.56 

06 

6.0 

10.39 

12460 

2657 

E    2.625 

4.00 

60 

10  50 

10870 

2329 

-2494 

F    2.625 

406 

6.0 

10  66 

12000 

2496 

D    2  25 

3.50 

6.0 

7.875 

7020 

2292 

E    2.31 

3.625 

6.0 

8.37 

10250 

3525 

.2822 

F    2.25 

3.44 

60 

7.74 

7840 

2650 

D    2  50 

3.94 

60 

9.85 

8320 

1959 

E    2.50 

3.94 

6.0 

9.85 

7850 

1820 

-1863 

F    2.56 

3.94 

60 

10.08 

8000 

1811 

D    2.50 

3.875 

6.0 

9.69 

8730 

2093 

E    2.50 

3.875 

60 

9.69 

7410 

1776 

-1672 

Round  corners,  grooved  longitudinally. 

F    2.50 

3.875 

60 

9.69 

4790 

1148 

D    2375 

3.94 

6.0 

9.36 

9690 

2365 

E    2.31 

4.00 

6.0 

9.24 

8000 

1948 

-2299 

Round  corners. 

F    2.375 

4.125 

60 

9.79 

11610 

2584 

D    2.75 

4.06 

6.0 

11.17 

6780 

1346 

E    2.81 

4.00 

60 

11.24 

6000 

1197 

-1195 

Round  corners. 

F    2.75 

4.00 

6.0 

11.00 

5100 

1043 

D    262 

4.06 

6.0 

10.64 

8000 

1668 

E    2  55 
F    2.55 

4  19 
4.25 

6.0 
6.0 

10  68 
10.83 

9010 
7770 

1811 
1518 

-1666 

Round  corners,  grooved  transversely. 

D    3  00 

3  875 

6.0 

11  .62 

9760 

1850 

E    3.06 

3.94 

6.0 

12.06 

7830 

1483 

-1688 

Round  corners,  grooved  longitudinally. 

F    3.00 

3.75 

60 

11.25 

7640 

1630 

D    2.44 

4.125 

6.0 

10.06 

11660 

2527 

E    2.375 

4.25 

6.0 

10.09 

12710 

2667 

-2428 

Round  corners. 

F    2.375 

4.18 

6.0 

9.98 

9640 

2091 

D    2  .06 

3.56 

6.0 

7.33 

5750 

1982 

^) 

E    2.06 

3.50 

6.0 

7.21 

8000 

2853 

^2269 

F    2.06 

3.50 

6.0 

7.21 

5530 

1972 

j 

..    2.75 

3.75 

6.0 

10.31 

7150 

1664 

Only  one   specimen.     Round   corners, 
grooved  longitudinally. 

For  numbers  9,  10, 11,  12,  13, 14,  and  16,  the  dimensions  are  those  of  the  estimated 
equivalent  rectangular  sections. 


22 


BUICK  FOR  STREET  PANEMENTS. 


i  i 

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BRICK   FOR    STREET   PAVEMENTS. 


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BRICK  FOR  STREET  PAVEMENTS. 


TABLE  No.  6.— COMPARATIVE  RANK. 


RANK. 

ABSORPTION 
CUBES. 

ABSORPTION 
WHOLE 
BRICKS. 

CRUSHING 
STRENGTH. 

TRANSVERSE 
STRENGTH. 

ABRASION 
AND  IMPACT. 

SPECIFIC 
GRAVITY. 

First    

13 

1  &  15 

16 

5 

1 

1 

1 

13 

1 

7 

4 

16 

Third  

15 

10 

15 

6 

16 

3 

Fourth           

10 

7 

14 

14 

6 

7 

Fifth.  

5 

6 

4 

10 

14 

5-10  &  15 

Sixth  

7 

12 

7 

15 

5 

12 

Seventh  

3 

3 

10 

4 

7 

9 

Eighth    .  . 

9 

14 

5 

3 

15 

11 

Ninth         

16 

16 

6 

8 

13 

4  &  6 

Tenth  .  .  .-.  

11 

8 

13 

13 

8 

2 

Eleventh  

12 

11 

8 

9 

9 

14 

Twelfth  

8 

9 

9 

12 

11 

13 

Thirteenth      

4 

5 

2 

16 

10 

8 

Fourteenth  

14 

4 

3 

1 

3 

Fifteenth  

6 

2 

11 

2 

12 

Sixteenth  

2 

2 

11 

2 

i 

BRICK   FOR   STREET   PAVEMENTS. 


25 


TABLE  No.  7 — Loss  OF  BRICK   IN  TERMS  OF  GRANITE. 


SPECIMEN  NUM- 
BER. 

FIRST  RATTLER 
TEST. 

SECOND  RATTLER 
TEST. 

ENTIRE  RATTLER 
TEST. 

1 

1.0 

1.0 

1.0 

2 

8.1 

5.0 

5.1 

3 

3.8 

5.1 

4.9 

4 

1.9 

2.0 

2.0 

5 

3.0 

2.1 

2.2 

6 

2.6 

2.1 

2.1 

7 

3.0 

2.7 

2.7 

8 

2.6 

3.4 

3.3 

9 

2.0 

3.8 

3.7 

10 

1.7 

4.8 

4.5 

11 

2.1 

4.6 

4.3 

12 

2.5 

5.3 

5.0 

13 

1.4 

3.1 

2.9 

14 

1.4 

2.2 

2.1 

15 

20.0 

1.4 

2.9 

16 

1.4 

2.0 

2.0 

26 


BRICK  FOR  STREET  PAVEMENTS. 


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BRICK  FOR  STREET  PAVEMENTS.  27 

DESCRIPTION  OF  THE  TABLES. 

Table  No.  1  requires  but  little  description.  It  shows  the 
essential  chemical  ingredients  of  the  different  varieties  of 
bricks  tested  as  obtained  from  a  single  analysis  of  each  kind. 
Generally  the  sample  was  taken  from  the  crushed  cubes,  but 
where  we  failed  to  crush  them  pieces  were  taken  from  other 
broken  specimens,  using  the  common  mortar  and  pestle  for 
pulverizing.  Could  a  larger  quantity  of  each  variety  have 
been  ground  and  used  in  sampling,  or  a  greater  number  of 
analyses  have  been  made,  a  more  accurate  average  determi- 
nation would  have  been  obtained,  but  the  time  and  expense 
required  for  such  work  is  so  great  that  it  was  deemed  pru- 
dent to  limit  our  investigation  to  the  single  analysis.  It  is 
evident  that  an  inquiry  into  the  nature  of  the  material  of 
which  the  bricks  are  composed  is  the  proper  basis  for  a  study 
of  the  whole  matter,  and  should  next  be  followed  by  a  scru- 
tiny of  the  methods  of  combination.  These  searches  should 
then  be  followed  by  tests  of  the  goods  produced.  Without 
proper  clay  no  good  result  can  be  expected,  and  with  suita- 
ble materials  improperly  combined  failure  is  sure  to  follow. 
From  the  first  cause  I  would  cite  numbers  3  and  15,  as  not 
meeting  the  requirements  ;  from  the  second,  numbers  2,  11, 
and  12  are  conspicuous  examples. 

Could  our  analyses  have  been  made  from  the  clays  used, 
we  should  have  been  working  to  better  advantage  ;  but  that 
was  not  practicable  for  us  under  the  circumstances.  In  or- 
der to  show  that  the  results  obtained  are  entitled  to  credence, 
I  have  compiled  Table  No.  8  from  the  sources  named  in  its 
description,  which  shows  that  the  work  done  has  been  care- 
fully performed. 

Table  No.  2,  is  a  detailed  statement  of  the  results  of  the 
investigations  to  determine  ratios  of  absorption  and  specific 
gravities.  The  method  of  performing  the  work  has  been 
described.  Numbering  the  columns  from  left  to  right,  the 


28  BRICK    FOR    STREET    PAVEMENTS. 

first  is  the  specimen  number ;  the  second  is  the  weight  in 
grammes  of  the  cubes  lettered  "A"  after  being  dried;  the 
third  is  their  weight  after  soaking  twelve  hours  in  water ; 
the  fourth  is  the  excess  of  the  third  over  the  second,  which 
is  obviously  the  weight  of  moisture  absorbed  ;  the  fifth  is 
the  quotient  (multiplied  by  one  hundred)  of  the  fourth  di- 
vided by  the  second,  or  the  percentage  of  absorption ;  the 
sixth  is  the  weight  of  the  cube  in  water;  and  the  seventh  is 
the  specific  gravity.  This  was  determined  by  the  formula : 

W 

Specific  gravity=- 


'—  W 


In  which  W  equals  weight  before  immerson,  W  equals 
weight  after  immersion,  and  W"  equals  weight  in  water. 
The  remainder  of  the  table  details  similar  experiments  with 
whole  bricks,  using  a  less  accurate  means  of  determining 
weights,  column  eight  giving  the  letters  designating  the  mark- 
ing of  specimens  of  the  several  numbers  (it  will  be  noted  that 
these  bricks  appear  again  in  The  Rattler  Test  —  Table  No.  5)  ; 
column  nine  giving  the  weight  in  ounces  before  immersion  ; 
column  ten,  the  weight  after  soaking  seventy  hours  in  wa- 
ter ;  column  eleven  is  the  excess  of  ten  over  nine,  being  the 
weight  of  water  absorbed  ;  column  twelve  is  again  the  per- 
centage, or  the  quotient  multiplied  by  one  hundred  of  eleven 
divided  by  nine  ;  and  column  thirteen  is  the  mean  of  the 
two  results  from  specimens  of  the  same  number  in  column 
twelve. 

The  latter  test  is  not  one  of  great  accuracy,  and  the 
tabulated  results  can  not  show  all  of  the  influences  which 
should  be  taken  into  consideration.  For  example,  numbers 
three  and  fifteen  were  smooth,  clean  bricks  when  put  in  water, 
but  when  they  were  taken  out  their  surfaces  were  defaced 
l«v  numerous  indentations  caused  bv  the  dissolution  of  the 


BRICK  FOR  STREET  PAVEMENTS.  29 

contained  material.  This  loss  lessens  the  apparent  amount 
of  absorption,  and  unless  provision  is  made  for  determining 
it  in  each  case  it  can  not  be  measured.  It,  however,  re- 
veals a  serious  defect,  which  should  not  be  overlooked. 
Where  nothing  of  this  kind  is  apparent  the  test  is  a  very 
practical  one,  and  can  be  repeated  at  pleasure  with  the  ordi- 
nary counter-scale  and  but  little  trouble.  It  furnishes  a  very 
fair  test  of  the  absorbing  qualities  of  the  material. 

Table  No.  3  sets  out  in  detail  the  results  of  the  work 
done  to  ascertain  the  crushing  strength  of  the  materials 
tested.  The  method  of  preparing  the  specimens  having  al- 
ready been  described,  it  is  not  considered  necessary  to  set 
forth  in  further  detail  the  manner  of  arriving  at  the  results 
here  tabulated,  as  that  will  be  evident  from  a  mere  inspec- 
tion of  the  table.  A  glance  at  the  results  obtained  shows 
us  that  we  are  not  dealing  with  the  substance  ordinarily 
known  as  brick. 

In  Table  !N~o.  4  is  given  the  work  done  to  ascertain  the 
transverse  strength  of  the  material.  The  Riehle  testing  ma- 
chine of  Messrs.  Otten  &  Westenhoff  was  used  for  this 
purpose.  Three  whole  bricks  or  blocks,  lettered  D,  E,  and  F> 
of  each  variety  were  broken,  excepting  numbers  one  and 
sixteen,  of  which  but  one  each  could  conveniently  be  had. 
The  bricks  were  supported  on  knife  edges  six  inches  apart, 
and  the  load  was  applied  by  another  knife  edge  brought  to 
bear  midway  between,  and  parallel  to,  the  other  two ;  each 
point  of  bearing  being  protected  from  direct  abrasion  by 
two  or  three  thicknesses  of  blotting  paper. 

The  modulus  of  rupture  was  computed  by  the  ordinary 

formula: 

3  wz 


in  which  W  represents  the  breaking  weight  in  pounds,  6, 


30  BRICK    FOR   STREET    PAVEMENTS. 

and  Z,  the  "breadth,  depth,  and  length,  respectively,  all  in 
inches,  and  R  the  modulus  of  rupture  in  pounds.  If  the 
span  I  be  measured  in  feet,  while  6  and  d  are  measured  in 
inches,  the  formula  becomes 


Hence,  the  modulus  of  rupture  is  stated  by  Prof.  Rankine  to 
be  "  Eighteen  times  the  load  required  to  break  a  bar  of  one 
inch  square,  separated  at  two  points,  one  foot  apart,  and 
loaded  in  the  middle  between  the  points  of  support."  While 
this  is  the  ordinary  formula  used  in  the  text-books,  and 
identical  with  that  adopted  by  Prof.  Baker  in  his  recent 
publication  upon  "  The  Durability  of  Brick  Pavements,"  it 
should  not  be  confounded  with  that  commonly  employed 
for  determining  the  transverse  strength  of  material,  which  is 


I  W 


4ad 


In  which  R  represents  the  coefficient  of  transverse  rupture  ; 
W  the  breaking  weight;  a  the  sectional  area;  d  the  depth; 
I  the  length,  all  in  inches.  Results  obtained  by  the  latter 
formula  will  be  found  to  be  about  J  of  those  derived  from 
the  one  first  stated. 

In  the  table,  the  first  column  on  the  left  gives  the  speci- 
men numbers ;  the  second,  the  letters  by  which  they  were 
designated;  the  third  column  is  the  breadth  or  thickness; 
the  fourth,  the  vertical  depth;  the  fifth,  the  length  between 
supports,  all  of  these  dimensions  being  in  inches.  The  sixth 
column  is  the  product  of  the  third  by  the  fourth,  being  the 
area  in  square  inches.  The  seventh  is  the  weight  in  pounds 
at  which  the  specimen  was  broken ;  the  pressure  being  ex- 
erted by  the  continuous  working  of  the  pump  without  shock 


BRICK   FOR   STREET    PAVEMENTS.  31 

until  rupture  was  produced.  The  eighth  column  is  the  mod- 
ulus of  rupture  calculated  by  the  formula  first  ahove  given. 
This  formula  is  stated  in  Professor  Baker's  pamphlet,  page 
5,  in  the  following  form : 


The  letters  having  the  same  significance  as  above  given,  but 
a  moment's  inspection  shows  this  expression  to  be  identical 
with  that  used  in  calculating  the  table.  The  ninth  column 
shows  the  averages  of  the  three  results  given  in  column 
eight  for  specimens  of  the  same  kind  or  number. 

Table  No.  5  is  a  detailed  statement  of  "  The  Rattler 
Test,"  or  the  effort  to  measure  the  effect  of  abrasion  and  im- 
pact upon  the  specimens  submitted.  The  method  of  con- 
ducting the  test  has  already  been  briefly  outlined.  Tabulat- 
ing the  result  has  been  a  tedious  process,  but  it  has  been 
done  with  much  care,  and  is  believed  to  clearly  show  the  re- 
sults obtained  in  such  a  manner  that  the  value  of  the  test 
can  be  judged  from  a  correct  basis.  All  the  weights  were 
carefully  repeated,  and,  if  errors  have  been  made  in  the  cal- 
culations, all  the  work  is  given  in  detail,  so  that  corrections 
can  be  made  by  inquiring  minds  if  incorrect  results  are 
found  in  any  of  the  columns. 

Counting  from  the  left,- the  first  column  gives  the  speci- 
men number ;  the  second,  its  letter  (those  marked  G-  and  II 
having  just  come  from  their  bath  in  the  absorption  test — 
Table  No.  2) ;  the  third,  its  weight  in  ounces  when  placed  in 
the  rattler;  the  fourth,  its  weight  after  the  first  thousand 
revolutions,  or  at  the  end  of  the  first  test.  There  was  an  in- 
terval of  nearly  forty-eight  hours  between  the  first  and  sec- 
ond rattler  tests,  and  the  weighing  was  repeated  before 
placing  the  specimens  the  second  time  in  the  cleaner,  but  the 


OZ  BRICK   FOR    STREET   PAVEMENTS. 

loss  in  weight  by  evaporation  from  the  saturated  bricks  did 
not  appear  to  be  a  measurable  quantity  by  the  instrument 
used,  which  was  a  new  Fairbank  counter  scale,  weighing  to 
quarter  ounces.  The  fifth  column  is  the  excess  in  the 
weights  given  in  the  third  over  those  in  the  fourth,  or  the 
loss  in  ounces  of  each  specimen  in  the  first  test.  The  sixth 
column  gives  the  weight  of  each  specimen  at  the  end  of  the 
second  or  final  test.  In  a  few  cases,  there  was  uncertainty 
about  the  identity  of  some  specimens,  as  the  marks  had  been 
so  defaced,  but  in  all  instances  the  varieties  could  readily  be 
distinguished.  Where  figures  are  inclosed  in  parentheses, 
they  include  the  weights  of  the  pieces  which  had  been  broken 
off  and  were  of  sufficient  size  to  be  saved  and  weighed. 
The  seventh  column  is  the  excess  of  the  weights  given  in  the 
fourth  over  those  in  the  sixth,  being  the  loss  in  the  second 
test.  The  eighth  is  the  sum  of  the  seventh  and  fifth,  or  the 
difference  of  the  third  and  sixth,  being  the  total  loss  in  both 
tests.  The  ninth  is  the  quotient,  multiplied  by  100,  of  the 
fifth  divided  by  the  third,  or  the  percentage,  to  the  nearest 
tenth.  The  tenth  column  is  the  percentage  of  loss  in  the 
second  test,  and  is  obtained  by  dividing  one  hundred  times 
the  sum  of  the  losses  for  specimens  of  the  same  number, 
taken  from  column  seven,  by  the  sum  of  the  weights  of 
specimens  of  that  number,  taken  from  column  four.  The 
eleventh  column  is  calculated  in  the  same  manner,  using  the 
sum  of  the  weights  for  each  variety  or  number  as  given  in 
column  eight,  and  the  sum  of  the  weights  of  the  same  variety 
in  column  three. 

Table  No.  6  is  compiled  from  the  results  set  out  in  the 
preceding  five  tables ;  the  several  numbers  being  rated  with 
each  other  in  the  order  in  which  they  have  withstood  the 
various  tests  to  which  they  have  been  subjected.  It  shows 
some  rather  unexpected  results  and  is  worthy  of  very  care- 


BRICK    FOR    STREET    PAVEMENTS.  33 

ful  study.  The  rank  is  by  averaging  all  the  tests  of  each 
kind  for  each  number  or  variety  in  each  test.  Thus,  in  the 
absorption  tests,  those  numbers  showing  a  less  average  per- 
centage of  absorption  are  ranked  higher  than  those  showing 
a  greater  percentage.  In  crushing  strength,  those  showing 
a  higher  power  of  resistance  rank  above  those  showing  a 
less  endurance.  In  this  test,  unfortunately,  our  machine 
had  not  the  power  to  enable  us  to  properly  classify  the  better 
grades  of  material  tested,  but  the  rank  so  given  is  strictly  in 
accordance  with  the  results  of  the  work.  It  is  not  thought 
that  Xo.  16  is  absolutely  a  stronger  material  than  granite, 
but  one  of  the  granite  cubes  was  slightly  spalled  at  a  lower 
pressure  than  was  exerted  when  the  No.  16  cube  was  spalled, 
but  none  of  the  cubes  of  either  number  were  crushed,  hence 
the  actual  endurance  of  the  material  remained  undetermined. 
In  transverse  strength,  the  numbers  having  a  greater  average 
modulus  of  rupture  are  ranked  above  those  having  a  less, 
which  correctly  classifies  the  material  as  to  its  tenacity  under 
stress  as  it  was  applied  in  making  tests,  but  furnishes  but  a 
poor  criterion  by  which  to  judge  of  the  quality  of  brittleness 
under  percussion  or  shocks.  Under  abrasion  and  impact, 
the  numbers  are  ranked  according  to  the  percentages  of  loss 
in  the  second  rattler  test;  those  suffering  a  less  loss  being 
ranked  higher  than  those  suffering  a  greater  one. 

Table  No.  7  is  deduced  from  the  percentages  given  in 
table  RTo.  5,  the  loss  of  the  granite  being  taken  as  one.  The 
left  hand  column  gives  the  specimen  number;  the  second 
column  its  ratio  of  loss  in  the  first  test;  the  third  column  its 
ratio  of  loss  in  the  second  test,  and  the  fourth  column  its 
total  ratio  of  loss  in  both  tests.  For  purposes  of  comparison 
it  is  recommended  that  the  figures  in  the  third  column  be 
used.  It  will  be  seen  that  the  best  bricks  under  the  most 
3 


34  BRICK   FOR   STREET    PAVEMENTS. 

favorable  conditions  suffer  about  double  the  loss  which  the 
granite  does. 

Table  ~No.  8.  This  table  has  been  compiled  for  the  pur- 
pose of  comparing  the  work  of  other  investigations  with 
that  herein  described.  The  first  analysis  given  is  a  Stour- 
bridge  fire-clay  used  exclusively  for  the  manufacture  of  glass 
house  pots  and  furnace  linings.  It  is  a  coal  measure  clay 
and  probably  contained  traces  of  lime  and  magnesia,  but  no 
mention  of  such  ingredients  is  found  in  Mr.  Wills' s  analysis. 
The  second  analysis  by  the  same  chemist  is  of  a  clay  from  a 
like  source,  but  in  this  case  he  has  determined  the  percent- 
age of  lime  contained,  which  is  very  small  indeed.  These 
clays  are  mined  and  used  because  of  their  heat  resisting 
qualities,  and  are  principally  valuable  because  at  white  heat 
they  do  -not  readily  vitrify,  but  retain  their  form  and  tex- 
ture. The  third  analysis  is  of  a  Newcastle  fire-clay,  by  Mr. 
Taylor,  the  product  being  less  remarkable  for  resisting  heat 
than  wear.  It  is  to  be -observed  that  this  clay  contains  in- 
gredients which  at  a  white  heat  will  unite  or  vitrify,  but 
would  hardly  be  likely  to  become  fluid  or  even  sufficiently 
plastic  to  greatly  change  in  form.  It  is  quite  similar  to  our 
Nos.  4,  8,  and  14,  except  that  it  contains  much  less  iron.  The 
fourth  analysis,  from  Percy's  Metallurgy,  is  of  the  Glasgow 
fire-clay,  adapted  to  a  variety  of  metallurgical  uses,  is  an 
average  of  many  determinations  in  which,  unfortunately  for 
our  purposes,  the  percentage  of  alkalies  is  not  given.  With 
this  exception  it  gives  the  characteristic  ingredients  of  the 
coal  measure  fire-clays.  The  fifth  analysis  is  of  the  white 
clay  of  the  tertiary  formation  in  Dorset,  by  Professor  Way. 
It  is  used  for  the  manufacture  of  fire-brick  and  could  prop- 
erly be  termed  a  modified  fire-clay.  The  analysis  gives  the 
alkalies  as  "  alkalies  and  alkaline  earth,"  and  the  lime  as  a 
sulphate.  This  clay  contracts  very  greatly  in  the  process  of 


BRICK   FOR    STREET    PAVEMENTS.  35 

drying  and  burning,  to  counteract  which  tendency  it  is  cus- 
tomary to  incorporate  with  it  fine  sand  and  ground  burnt 
clay.  Number  six  is  the  Beacon  Hill  clay  from  the  Lower 
Bagshot  Beds,  which  withstands  the  high  temperatures  of 
furnace  linings  without  much  tendency  toward  vitrification, 
but  decrepitates  or  is  worn  away  by  passing  currents.  The 
seventh  analysis  is  taken  from  a  recent  publication  by  C.  P. 
Chase,  on  "  Brick  Pavements,"  and  gives  the  composition  of 
the  clay  used  in  the  manufacture  of  the  Hale  paving  brick. 
Mr.  Chase  gives  the  moisture  at  212  degrees  as  2.08,  and 
combined  water  as  5.16,  but  does  not  determine  the  alkalies 
present,  if  any  were  contained  in  his  sample.  If  the  writer 
understands  what  is  meant  by  the  Hale  paving  brick,  this 
should  correspond  with  our  No.  2,  Mr.  Chase's  analysis  hav- 
ing been  made  from  the  clay  and  ours  from  the  brick,  but 
the  resemblance  is  not  very  close.  The  eighth  analysis  is 
copied  from  the  same  source  as  the  preceding  one.  The  ma- 
terial in  its  natural  position  more  nearly  resembles  a  fine- 
grained sandstone  than  a  bed  of  fire-clay,  but  it  pulverizes 
readily  on  exposure  to  the  atmosphere,  and  its  composition 
and  position  have  given  it  its  name.  From  it  is  manufac- 
tured the  Hay  den  block,  which  is,  in  reality,  a  tile  used  for 
paving  streets.  No  sample  of  this  material  was  furnished 
for  testing,  but  it  has  been  used  extensively  as  a  paver,  and 
in  some  localities  is  deservedly  popular.  When  properly 
burned  and  annealed  it  presents  a  homogeneous,  compact 
texture,  and  has  great  hardness  without  brittleness.  Many 
persons  would  say  that  the  material  was  "  perfectly  vitrified," 
but  that  expression  needs  specific  explanation  to  be  at  all  in- 
telligible. The  ninth,  tenth,  and  twelfth  analyses  are  copied 
from  the  same  author,  who  also  gives  the  specific  gravity, 
crushing  strength,  and  percentage  of  absorption  of  the  bricks 
manufactured  from  these  clays.  While  he  classes  them 


30  BRICK  FOR  STREET  PAVEMENTS. 

among  "  our  best  paving  brick,"  he  gives  no  statistics  show- 
ing their  enduring  qualities  in  actual  use.  They  would  more 
nearly  coincide  with  our  No.  3  than  any  other  sample  tested, 
although  they  might  not  resemble  it  in  color.  The  writer 
would  not  regard  No.  10  as  a  very  promising  composition, 
but  all  of  these  clays  can  be  melted  or  vitrified  very  readily 
so  as  to  present  a  compact  texture  that  will  not  absorb  moist- 
ure in  any  considerable  .amount.  The  eleventh  analysis  is 
from  the  same  author  of  a  clay  used  by  the  American  Brick 
and  Tile  Company,  of  Phillipsburg,  New  Jersey.  This  com- 
position is  also  said  to  contain  sulphur  0.89,  and  phosphoric 
acid  0.13.  No  further  information  is  given  regarding  the 
product  except  that  the  crushing  strength  averages  from 
7,000  to  7,500  pounds  per  square  inch.  The  thirteenth  and 
fourteenth  analyses  were  made  by  Otto  Wuth,  of  Pittsburg, 
the  first  being  of  the  Porter  fire-brick  and  the  second  of  the 
ground  clay  from  which  such  bricks  are  manufactured. 
These  compositions,  it  will  be  noticed,  are  quite  similar,  ex- 
cept that  the  brick  has  had  the  moisture  driven  off  in  burn- 
ing. They  closely  resemble  our  No.  14,  except  that  we  find 
a  much  higher  percentage  of  the  alkalies,  and  herein  lies 
the  marked  distinction  between  the  fire-clay  brick,  which  is 
suitable  for  furnace  lining,  and  the  one  adapted  to  use  in 
street  paving. 

THE  CHEMISTRY  OF   BRICK  MANUFACTURING. 

The  alkalies  or  potash  in  the  clays  is  a  residuum  of  de- 
cayed organic  matter.  It  is  an  active  fluxing  agent,  and  in 
the  process  of  burning,  or  so-called  vitrification,  causes  an 
amalgamation  of  the  iron  and  silica  components  which  imparts 
a  metallic  tone  or  ring  to  the  brick  when  struck.  When 
aided  by  finely  pulverized  lime  or  magnesia  in  the  presence 
of  a  large  percentage  of  iron,  a  pale  double  silicate  of  lime 


BRICK    FOR    STREET    PAVEMENTS.  37 

and  iron  is  formed,  imparting  a  buff  tint  to  clays  that  would 
otherwise  burn  red.  In  the  fire-clays  less  than  half  of  one 
per  cent  of  potash  or  alkali  produces  no  noticeable  result,  and 
the  product  has  good  heat  resisting  qualities,  but  when  from 
one  to  three  per  cent  of  this  ingredient  is  found  in  the  clay 
and  it  contains  from  four  to  eight  per  cent  of  iron,  which  it 
generally  does,  with  perceptible  quantities  of  lime  and  mag- 
nesia at  a  high  temperature  (usually  a  white  heat),  these  flux- 
ing components  form  vitreous  combinations  with  the  silica, 
producing  a  brick  quite  useless  for  resisting  heat,  but  when 
the  texture  is  uniform  throughout,  and  it  is  allowed  to  cool 
gradually,  without  coming  in  contact  with  cold  air  until  be- 
low the  temperature  of  boiling  water;  or,  in  other  words,  is 
properly  annealed,  you  have  the  so-called  vitrified  brick, 
which  absorbs  about  two  per  cent  or  less  of  moisture,  and 
has  great  strength  to  resist  crushing  or  abrasion.  This 
product  may  be  used  quite  fearlessly  for  street  paving. 

With  the  plastic  clays  or  shales  the  melting  or  vitrifica- 
tion occurs  at  a  lower  temperature,  and,  owing  to  the  fact 
that  the  ingredients  are  seldom  uniformly  mingled,  there  is 
greater  danger  of  melting  the  bricks  together  in  the  kiln,  or 
of  leaving  many  of  them  without  vitrification.  To  render 
them  apparently  impervious  to  moisture,  many  manufactur- 
ers have  adopted  the  plan  of  glazing  them  with  salt,  which 
may  be  beneficial  in  some  respects,  but  is  objectionable  in 
others.  These  clays  usually  contract  to  a  greater  extent  in 
the  process  of  drying  and  burning  than  the  fire-clays  do, 
tuid  hence  are  more  liable'  to  be  warped  from  their  proper 
form,  or  show  injurious  fire  cracks.  But  no  clay  can  be 
made  into  a  good  street  paving  brick,  unless  the  process  of 
firing  or  burning  be  continuously  progressive  and  compara- 
tively slow  to  the  maximum  temperature,  and  the  cooling 
down  be  gradual  and  continuous.  This  can  not  be  done  in 


BRICK    FOR    STREET    PAVEMENTS. 

the  ordinary  clamp-kiln.  A  broken  brick  showing  varieties 
of  texture  or  color  is  a  certain  indication  of  defective  com- 
bination or  burning,  and  the  fault  is  fully  as  liable  to  be  in 
the  burning  as  elsewhere.  Uniformity  in  the  product  of  the 
kiln  is  a  necessary  condition  to  the  successful  manufacture 
of  clay  of  any  kind  into  proper  form  to  be  used  for  street 
paving ;  and  only  with  such  clays,  and  such  appliances  as 
will  enable  the  manufacturer  to  attain  this  result,  can  he 
reasonably  hope  to  achieve  success. 

DISCUSSION    OF    THE    TESTS. 

With  the  information  now  before  us,  what  brick  shall  be 
selected?  If  the  tests  were  of  uniform  value  the  numbers 
should  range  in  horizontal  lines  across  Table  No.  6,  the  best 
material  at  the  top  and  the  poorest  at  the  bottom  ;  but  we  do 
not  obtain  such  results.  There  are  other  considerations  that 
can  not  appear  in  the  tables.  Nearly  50,000  square  yards  of 
surface  are  to  be  paved,  and  the  availability  must  be  consid- 
ered. That  which  can  be  promptly  furnished  in  large 
quantities  should  be  chosen,  even  though  an  article  may  be 
manufactured  which  is  better  in  some  respects,  but  unattain- 
able without  great  delay.  But  people  wrhose  opinions  are 
entitled  to  great  respect  will  honestly  differ  as  to  the  relative 
value  of  the  several  tests.  For  example,  Prof.  Baker,  in  his 
pamphlet  on  "  Brick  Pavements,"  expresses  the  opinion  de- 
cidedly that,  "As  a  test  of  the  quality  of  brick  or  stone,  the 
crushing  strength  is  practically  worthless."  (Baker  on  Brick 
Pavements,  p.  8.)  He  demonstrates  in  a  concise  manner  that 
the  weight  on  the  wheel  of  a  loaded  vehicle  is  not  likely  to 
crush  a  brick,  even  though  it  be  soft.  Yet  the  profession  gen- 
erally have  considered,  and  probably  will  continue  to  regard  it 
as  essential,  that  the  constructing  engineer  should  be  informed 
as  to  the  crushing  strength  of  the  materials  which  he  uses, 


BRICK    FOR   STREET    PAVEMENTS.  39 

and  that,  in  connection  with  other  information,  it  is  an 
efficient  aid  in  determining  the  relative  value  of  different 
building  materials.  However,  it  is  only  one  of  the  elements 
to  be  considered.  For  example,  the  crushing  strength  of  cast 
iron,  is  about  twice  that  of  wrought  iron,  and  of  steel  more  than 
twice  that  of  cast  iron,  but  this  does  not  make  cast  iron  worth 
twice,  nor  steel  four  times  as  much  as  wrought  iron  for  use 
under  compressive  stress.  In  fact,  the  best  practice  adopts 
wrought  iron  in  preference  to  either  of  the  others  for  many  po- 
sitions, but  a  knowledge  of  the  sustaining  power  of  the  mate- 
rial is,  and  must  be,  essential  to  the  designer.  A  study  of  the 
preceding  tables  shows  that  those  specimens  having  a  high 
crushing  strength  also  rank  well  in  the  test  for  abrasion 
and  impact,  and  it  is  reasonable  to  assume  that  the  power  to 
sustain  great  weight  without  crushing  would  be  necessary  to 
the  durability  of  a  block  placed  in  a  roadway,  and  subjected 
to  the  attrition  and  grinding  due  to  that  position.  It  is  true 
that  many  experiments  or  tests  are  conducted  in  such  a 
manner,  and  the  results  given  so  incoherently,  that  they  are 
of  little  value,  but  where  the  work  is  carefully  done,  and 
the  record  clearly  set  out,  so  that  knowledge  of  the  com- 
parative strength  of  different  substances  can  be  gained  from 
it,  information  regarding  the  crushing  strength  of  any  pav- 
ing material  to  be  used  in  the  form  of  blocks,  will  be  sought 
and  esteemed  as  of  great  merit  in  determining  the  value  of 
such  material.  A  recent  circular  from  the  State  of  New 
York  has  been  placed  in  the  hands  of  the  writer,  in  which 
it  is  stated  over  a  name  preceding  the  title  of  civil  engineer, 
that  the  "  average  resistance  to  crushing  per  square  inch  is  44,- 
000  pounds  "  for  a  certain  description  of  brick  which  had  been 
tested  by  him.  Now,  if  that  civil  engineer  had  informed  the 
public  at  large  by  what  steps  he  had  arrived  at  that  remarkable 
conclusion,  he  would  have  conferred  a  benefit  upon  his  fellow 


40  BRICK   FOR    STREET    PAVEMENTS. 

men.  The  same  circular  contains  further  information  as  fol- 
lows :  "  Under  an  abrasive  test  equal  to  a  traffic  tonnage  of 
100,000  tons  per  inch  of  width,  the  loss  was  nine-sixteenths 
of  an  inch,  or  six  and  one-fourth  per  cent  of  the  depth ;  thus 
under  a  daily  traffic  of  100  tons  per  foot  ot  width  of  street, 
this  brick  would  have  a  traffic  life  of  twenty-eight  years." 
That  conclusion  appears  to  be  quite  definite  and  satisfactory, 
but  there  are  ignorant  people  at  large  who  know  neither 
just  what  that  abrasive  test  might  be,  nor  by  what  process 
of  reasoning  such  a  result  is  reached.  Some  people  might 
think  that  a  daily  traffic  of  100  tons  per  foot  of  width  for  a 
period  of  twenty-eight  years  would  not  be  equal  to  a  traffic 
tonnage  of  100,000  tons  per  inch  of  width,  and  thus  conclude 
that,  if  the  first  premise  is  correct,  such  a  pavement  would 
be  good  for  at  least  two  or  three  centuries;  even  upon  the 
assumption  that  when  it  was  half  worn  out  the  abutting 
owners  might  want  it  renewed  for  a  change. 

The  work  done  at  this  time  for  determining  crushing 
strength  is  very  incomplete,  owing  to  the  limited  capacity 
of  the  machine,  but  it  is  believed  to  be  accurate  as  far  as  it 
extends,  and  enables  us  to  properly  classify  the  specimens 
not  having  a  resisting  capacity  exceeding  13,000  pounds  per 
square  inch. 

THE  ABSORPTION  TESTS. 

For  this  class  of  paving  material,  a  low  ratio  of  absorp- 
tion is  held  by  many  to  be  a  most  essential  condition,  and 
therefore  that  this  test  is  of  the  greatest  importance.  In  our 
work  this  the.ory  has  not  been  accepted.  Of  all  the  speci- 
mens tested  there  is  but  one  (No.  2)  which  should  be  rejected 
because  of  its  excessive  absorption  alone,  were  all  other 
characteristics  satisfactory.  Manufacturers  have  been  told 
so  frequently  that  a  non-absorbent  product  is  a  necessary 
condition  for  marketable  goods,  it  is  so  easy  for  them  to 


BRICK    FOR     STREET     PAVEMENTS.  41 

bring  the  rate  down  to  two  or  three  per  cent,  and  the  test 
can  be  so  readily  made,  that  but  few  street  paving  bricks  are 
in  the  market  which  absorb  moisture  as  freely  as  any  of  the 
stone  blocks  except  granite.  It  is  probably  unfortunate  that 
no  variety  of  stone,  other  than  Georgia  granite,  was  included 
in  the  tests  made,  but  sufficient  experiments  have  been  made 
with  the  various  building  stones  to  show  that  when  the  per- 
centage of  absorption  is  three  or  less,  and  the  material  is 
not  laminated,  they  are  neither  perceptibly  softened,  nor 
made  susceptible  of  destruction  by  climatic  influences.  Me- 
dina sandstone  absorbs  from  two  to  four  per  cent  of  moist- 
ure. Oolitic  limestone  absorbs  from  three  to  five  per  cent, 
yet  no  one  asserts  that  either  of  these  stones  is  softened  or 
affected  detrimentally  on  this  account,  and  the  first  is  a  stand- 
ard paving  stone.  Again,  of  the  specimens  crushed  or 
subjected  to  abrasion,  there  is  no  indication,  unless  it  be  BTo. 
2,  in  the  Rattler  test,  that  any  one  was  weakened  by  its  pre- 
vious soaking.  Therefore,  while  it  is  undoubtedly  true  that 
a  strictly  non-absorbent  material  is  the  best,  yet,  among  the 
paving  bricks  having  percentages  of  absorption  lower  than 
three,  while  the  advantage  of  an  exceedingly  low  rate  should 
not  be  ignored,  other  features  may  be  considered.  For  in- 
stance, !N"o.  13  is  shown  to  absorb  less  moisture  than  granite, 
and  where  it  is  not  to  be  subjected  to  an  excessive  traffic, 
should  on  this  account  be  favorably  considered,  but  its  en- 
durance under  severe  tests  appears  to  be  exceeded  by  some 
of  the  other  varieties. 

TRANSVERSE  STRENGTH. 

The  manner  in  which  the  transverse  strength  of  the 
specimens  submitted  was  determined  has  been  described  and 
tabulated,  but  in  doing  the  work  much  information  was 
gained  that  could  not  be  written  out.  An  unexpected  de- 


4-  BRICK    FOR    STREET     PAVEMENTS. 

gree  of  strength  was  exhibited  by  a  majority  of  the  speci- 
mens. While  this  test  shows  the  tenacity  of  the  material 
under  a  stress  continually  increasing  to  the  point  of  rupture,. 
it  gives  but  little  information  about  the  ability  of  the  same 
substance  to  withstand  the  effect  of  blows  or  shocks.  The 
behavior  of  the  bricks  at  the  instant  of  rupture  is  instruct- 
ive. Some  of  those  which  carried  the  greatest  weights  were 
much  shattered.  One  of  the  number  fives  broke  into  three 
triangular  pieces  of  nearly  equal  size.  Nearly  every  speci- 
men which  exhibited  the  characteristic  vitrified  appearance,, 
threw  off  flint-like  spalls,  and  presented  an  irregular  fract- 
ure. Those  specimens  which  in  other  tests  manifested  the 
greatest  endurance  were  usually  parted  by  a  clean  fracture 
almost  at  right  angles  with  the  brick,  directly  beneath  the 
central  bearing,  like  the  granite ;  while  those  having  interior 
defects  of  any  kind  would  separate  at  any  point  between  the 
outer  bearings.  This  test,  therefore,  is  of  much  value  to  the 
experimenter,  but  the  tabulated  result  is  not  a  sure  indica- 
tion of  the  value  of  the  material  for  street  paving  purposes. 

ABRASION  AND  IMPACT. 

The  manner  of  conducting  this  work  has  been  so  fully 
described,  and  the  results  set  out  in  such  detail  in  Tables  5 
and  7,  that  further  comment  is  hardly  necessary,  yet  it  is 
plain  that  it  presents  no  condition  at  all  similar  to  that 
which  obtains  in  actual  service.  The  bricks  are  loose  and 
battered  upon  all  surfaces,  whereas  in  the  pavement  they 
are  held  firmly  in  place  and  subjected  to  abrasion  upon  one 
side  only.  But  in  this  case  they  were  all  subjected  to  the 
same  treatment,  and  their  losses  should  give  a  fair  measure 
of  their  relative  powers  of  resistance.  "  The  Rattler  Test " 
has  been  frequently  repeated  by  various  parties,  and  a  prac- 
tice is  coming  in  vogue  of  assuming  that  a  half  hour  or  an 


BRICK    FOR    STREET     PAVEMENTS.  43 

hour  in  the  rattler  is  equivalent  to  a  year's  wear  in  the  pave- 
ment under  a  given  amount  of  traffic,  and  from  this  assump- 
tion the  probable  life  of  the  brick  in  actual  use  in  the  street 
is  calculated.  By  a  somewhat  similar  course  of  reasoning, 
although  the  premises  are  more  fully  and  fairly  detailed, 
Professor  Baker  has  calculated  Table  No.  7,  given  on  pages 
32  and  33  of  his  pamphlet  on  Brick  Pavements,  in  which 
the  life  of  a  pavement  made  of  each  of  the  varieties  of  brick 
which  he  tested,  is  given  in  certain  streets  of  ten  of  the 
principal  cities  of  this  country.  The  daily  traffic  tonnage  is 
taken  from  Captain  Greene's  statistics,  and  the  results  as 
tabulated  are  remarkable.  His  poorest  brick  would  last  four 
years  on  Broadway,  New  ^ork,  and  one  hundred  and  sixty- 
five  years  on  Olive  street,  St.  Louis ;.  while  his  best  brick 
would  last  thirty-eight  years  on  Broadway,  and  fifteen  hun- 
dred and  twenty  years  on  Olive  street.  The  writer  does  not 
dispute  such  conclusions,  but  has  no  facts  from 
lar  inferences  can  be  drawn. 

STATISTICS  OF  TRAFFIC  AND  DURABILILTY  OF 

Data  regarding  the  traffic  tonnage,  and  the  effect  of 
wear  on  street  pavements  and  highways,  has  not  been  col- 
lected and  preserved  in  this  country  in  such  form  as  to  be 
available  for  ready  reference.  A  few  years  since,  Captain  F. 
Y.  Greene  prepared  a  paper,  "An  Account  of  Some  Observa- 
tions of  Street  Traffic,"  which  was  published  in  Volume  15 
of  the  transactions  of  The  American  Society  of  Civil  Engi- 
neers. The  observations  were  made  by  employes  of  The 
Barber  Asphalt  Paving  Company,  under  Captain  Greene's 
directions,  during  the  months  of  October  and  November, 
1885,  in  the  ten  large  cities  in  which  that  company  had 
offices  and  works.  "  The  agent  in  each  city  was  instructed 
to  select  the  three  streets  in  that  city  paved  with  stone, 


44  BRICK   FOR   STREET    PAVEMENTS. 

asphalt,  and  wood  (if  any  existed),  which,  by  common  re- 
port, had  the  heaviest  traffic  in  the  class  of  pavement  used 
on  that  street.  The  record  was  in  every  case  made  on  six 
consecutive  days  (Sundays  omitted),  at  the  same  place,  and 
it  was  continuous  from  7  A.  M.  to  7  P.  M.,  except  when  dark- 
ness prevented.  No  addition  was  made  for  this  omission  ; 
no  record  was  kept  during  the  night,  and  no  addition  was 
made  as  an  estimate  of  night  traffic."  "  The  traffic  is  di- 
vided into  three  classes,  light  weight  (less  than  one  ton), 
medium  weight  (between  one  and  three  tons),  and  heavy 
weight  (more  than  three  tons). 

The  Captain  says  :  "  I  have  discarded  the  weight  of  the 
horses  altogether,  not  because  they  do  not  constitute  a  factor 
in  the  wear  of  the  pavement,  but  because  they  were  dis- 
carded in  the  English  reports,  and  I  desired,  as  far  as  possi- 
ble, to  make  comparisons  with  them."  .  .  .  "To  obtain 
the  tonnage,  I  estimated  the  light  weight  vehicles  to  average 
one-half  ton  each  (including  their  loads),  the  medium  weight 
two  tons,  and  the  heavy  weight  four  tons." 

r  l-horse  carriages,  empty  or  loaded. 

LIGHT  WEIGHT  INCLUDED -j  l-horse  wagons,  empty  or  light-loaded. 

(.  l-horse  carts,  empty. 


fl-1 
,.1-1 

I  2-1 


l-horse  wagons,  heavy-loaded. 
l-horse  carts,  loaded. 
-horse  wagons,  empty  or  light-loaded. 


ormore 


"  The  average  tonnage  per  vehicle  ranges  from  0.68  on 
Fifth  avenue  (New  York)  to  2.08  on  a  portion  of  Wabash 
avenue  (Chicago).  On  Fifth  avenue,  91  per  cent  of  all  the 
vehicles  weigh  less  than  one  ton,  while  on  Wabash  avenue, 
only  25  per  cent  of  them  have  so  little  weight.  The  general 
average  for  all  the  cities  is  as  follows  :  Less  than  one  ton, 
67  per  cent;  between  one  and  three  tons,  26  per  cent  ;  more 


BRICK  FOR  STREET  PAVEMENTS.  4£ 

than  three  tons,  7  per  cent.  The  average  tonnage  per  foot 
in  each  city,  so  far  as  here  observed,  varies  from  151  in  New 
York  to  30  in  Buffalo,  and  the  general  average  is  77.  For 
all  the  cities  in  the  table,  the  average  daily  tonnage  per  foot 
of  width  is  77,  and  varies  from  273  tons  on  Broadway  to  7 
tons  on  a  granite  street  in  St.  Louis.  The  average  weight 
per  vehicle  is,  for  all  the  cities,  1.15  tons.  The  average 
width  of  street  between  curbs  is  44  feet." 

This  is  believed  to  be  the  first  carefully  prepared  census 
of  travel  made  public  in  this  country,  and  it  was  published 
by  an  officer  of  an  asphalt  paving  company.  It  is  fair  to 
presume  that  one  object  in  view  was  to  show  the  durability 
of  that  kind  of  pavement  under  heavy  traffic.  Since  its 
publication,  a  few  annual  reports  have  contained  statistics 
upon  the  subject,  and  the  investigation  has  been  greatly  ex- 
tended by  the  different  asphalt  paving  companies.  Obvi- 
ously, information  of  this  kind  should  be  officially  compiled 
by  municipal  officers  upon  a  uniform  system  throughout  the 
country  and  its  scope  materially  extended.  The  effect  or 
wear  upon  the  roadway  of  an  observed  traffic  tonnage  should 
be  given,  which  has  not  been  done  except  in  a  few  of  the 
English  reports,  and  there  mainly  in  cost  of  maintenance 
or  repairs.  Reports  from  Washington  have  given  some  data 
as  to  the  cost  of  maintenance  of  certain  pavements,  and  the 
English  reports  are  usually  quite  explicit  upon  this  point; 
but  it  would  greatly  benefit  all  municipal  corporations  in  this 
country,  were  each  to  keep  a  record  of  the  kind  of  street  im- 
provements made,  their  manner  and  cost  of  construction; 
their  durability  and  expense  of  maintenance,  under  a  traffic, 
the  volume  of  which  could  be  noted  with  reasonable  accu- 
racy, at  but  trifling  expense.  The  omission  of  the  horses 
from  the  traffic  census  is  clearly  a  fault,  as  we  know  that 
they  assist  largely  in  wearing  the  roadway.  For  example, 


46  BRICK    FOR    STREET    PAVEMENTS. 

between  the  rails  of  street  car  tracks  upon  lines  operated  by 
horses  or  mules,  the  wear  of  the  pavement  is  due  almost  ex- 
clusively to  this  cause,  and  it  is  known  to  be  very  great. 
The  tonnage  of  vehicles,  as  estimated  by  Captain  Greene,  is 
heavier  than  many  observers  would  assume  it  to  be,  and  the 
percentage  to  be  added  for  the  weight  of  animals  will  vary 
with  the  nature  of  the  traffic,  being  greater  with  the  light 
and  less  with  the  heavy  traffic.  His  estimate  being,  that  on 
Fifth  avenue,  which  carries  91  per  cent  light  traffic,  the  ad- 
dition should  be  about  85  per  cent  for  the  horses,  while  on 
Wabash  avenue,  where  but  25  per  cent  is  light  traffic,  the 
addition  should  be  only  about  40  per  cent.  The  effect  of  the 
horse's  shoe  upon  the  street  surface  is  modified  by  the  nature 
of  the  pavement.  Probably  sheet  asphalt  suffers  as  little 
from  it  as  any  known  form  of  wearing  surface,  unless  the 
blows  fall  successively  upon  the  same  place  and  thus  effect  a 
displacement  of  the  material.  The  bowlder  is  seldom  scarred 
by  it,  hence  the  material  of  the  cobble  stone  pavement  is 
practically  indestructible  from  this  cause.  Granite  blocks 
are  spalled  and  rounded  until  they  assume  the  form  of  bowl- 
ders, and,  if  very  hard,  become  exceedingly  slippery  and  af- 
ford insecure  footing.  Brick  pavements  would  be  rapidly 
destroyed  were  the  bricks  as  widely  separated  as  granite 
blocks  usually  are,  but  being  placed  in  close  contact,  there  is 
little  room  for  the  rounding  away  of  corners.  The  brick 
surface  is,  however,  affected  as  it  would  be  by  receiving  a 
like  blow  from  a  cutting  tool  or  chisel  of  similar  form. 
From  this  cause,  will  result  by  far  the  greater  portion  of  the 
wear,  since  the  pavement,  when  unbroken,  will  be  sufficiently 
smooth  to  present  but  slight  obstacles  to  the  rolling  upon  it 
of  the  wheels  of  vehicles,  and  it  will  suffer  comparatively 
little  from  that  cause.  The  blow  delivered  by  the  animal's 
shoe  will  be  greatly  increased  at  high  speeds.  It  would, 


BRICK   FOR    STREET    PAVEMENTS.  47 

therefore,  appear  to  be  proper,  that  upon  avenues  carrying 
suburban  travel,  a  census  of  traffic  should  take  cognizance  of 
the  element  of  speed. 

THE  PROBABLE  DURABILITY  OF  A  BRICK  PAVEMENT. 
This  chipping  or  abrasion  of  the  surface  by  the  shoes  of 
animals  traveling  upon  it  will  be  its  severest  trial,  and  since 
no  definite  statistics  are  available  by  which  to  compute  the 
traffic  tonnage  to  which  it  will  be  subjected,  and  no  test  has 
been  made  which  serves  as  an  actual  measure  of  the  wear 
of  a  pavement  under  a  given  tonnage,  the  probable  durabil- 
ity of  this  street  can  not  be  stated,  but  can  only  be  predi- 
cated upon  the  endurance  of  the  brick  as  compared  with  the 
granite.  Judging  this  street  by  others  upon  which  the  cen- 
sus of  travel  has  been  taken,  it  seems  fair  to  assume  that  the 
traffic  will  not  greatly  exceed  60  tons  per  foot  of  width  per 
day,  including  the  weight  of  horses,  which  will  probably 
embrace  one-half  of  it.  The  surface  of  a  granite  block 
pavement,  as  ordinarily  constructed,  is  about  75  per  cent 
granite,  while  a  brick  pavement  is  about  90  per  cent  brick. 
There  is,  therefore,  about  20  per  cent  more  brick  than  gran- 
ite to  resist  wear.  The  brick  surface  is  comparatively 
smooth,  while  the  granite  is  uneven.  Wheels  will  roll 
smoothly  over  the  brick,  while  they  will  jolt  over  the  granite 
with  a  continual  succession  of  blows.  Let  it  be  assumed 
that  the  wear  due  to  horses  on  the  brick  will  be  120  per  cent 
of  that  due  to  the  same  cause  on  the  granite,  and  the  wear 
due  to  vehicles  on  the  granite  is  200  per  cent  of  that  due  to 
the  same  cause  on  the  brick :  it  follows  that  the  total  ef- 
fect on  the  brick  is  but  80  per  cent  of  that  on  the  granite. 
Now  we  find  in  table  No.  7  the  loss  of  the  brick  in  our 
abrasion  test  to  be  2.2  times  that  of  the  granite ;  a  traffic,  there- 
fore, which  wears  off  one  inch  from  the  granite  pavement 


48  BRICK   FOR   STREET    PAVEMENTS. 

will  wear  one  and  two-thirds  inches  from  the  brick ;  or, 
the  time  required  to  wear  an  inch  from  the  brick  will  be 
about  60  per  cent  of  that  required  to  wear  an  inch  from 
the  granite.  No  record  is  known  to  exist  showing  that 
amount  of  wear  from  a  granite  block  pavement  under  a 
similar  traffic,  but  about  five  times  the  tonnage  has  worn 
some  portions  of  our  city  pavements  to  about  that  depth 
in  four  years.  The  estimated  traffic  is  about  60  percent  of  that 
on  Fourth  street  between  Walnut  and  Race  streets,  exclud- 
ing street  cars,  and  quite  similar  in  character,  taking  the  en- 
tire width  of  pavement  (omitting  car  tracks),  and  five  years' 
wear  has  been  estimated  to  have  reduced  the  blocks  one- 
fourth  of  an  inch.  This  would  seem  to  justify  the  belief 
that  this  pavement  should  be  in  fair  condition  after  ten  years* 
traffic  shall  have  passed  over  it. 

MUNICIPAL  METHODS. 

A  cause  for  the  lack  of  definite  statistics  upon  these 
matters  is  apparent  when  municipal  methods  are  considered. 
American  civil  engineers  have  achieved  a  world- wide  repu- 
tation for  the  boldness  and  originality  of  their  designs,  the 
skill  exhibited  in  their  execution,  and  the  economy  shown  in 
attaining  results.  Great  industrial  establishments  have  been 
built,  lines  of  transportation,  with  all  the  works  appertain- 
ing thereto,  have  been  by  them  located  and  constructed,  and 
they  are  accredited  with  being  well  toward  the  van,  and  of 
contributing  their  full  share  toward  the  progress  and  devel- 
opment of  the  country.  In  all  such  works  facts  have  been 
collected  and  compiled,  so  that  reliable  data  is  available. 
Manufacturers  are  willing  to  guarantee  a  given  mileage  for 
their  steel  rails  or  car  wheels,  or  a  given  strength  for  their 
iron  and  steel,  from  data  made  available  by  engineers,  but  in 
municipal  matters  the  conditions  or  the  results  are  in  noway 


BRICK   FOR    STREET    PAVEMENTS.  49 

similar.  The  total  amount  of  money  annually  expended  by 
the  municipalities  of  the  country  in  opening,  improving, 
cleaning,  and  repairing  streets  and  highways,  is  an  enormous 
sum,  exceeding  that  applied  upon  all  other  public  works  in 
an  equal  length  of  time.  The  greater  part  of  this  fund  is 
nominally  disbursed  under  the  supervision  of  engineers,  but 
the  results  are  not  such  as  to  add  materially  to  the  renown 
of  the  profession,  or  to  supply  exact  data  for  their  guidance 
in  present  or  future  works  of  this  character.  One  reason  for 
this  appears  to  be  found  in  the  fact  that  these  funds  furnish 
the  greatest  of  the  existing  causes  of  activity  in  local  pol- 
itics. Municipal  statesmanship  is  developed  in  levying, 
watching,  and  disbursing  this  money.  Laws  providing  for 
its  collection,  control,  and  disbursement  have  been  enacted, 
termed  the  municipal  code,  which  is  more  complex  and  pe- 
culiar than  any  other  system  known  to  man.  Boards  and  Bu- 
reaus, Councils  and  Commissioners,  Supervisors  and  Direct- 
ors, Counselors  and  Barristers,  have  been  created  or  called  to 
govern  the  work,  guard  the  public  interest,  acquire  fame,  and 
enjoy  the  advantages  accruing  to  exalted  official  position.  The 
pervading  spirit  of  freedom  abroad  in  the  land  being  averse  to 
the  creation  of  such  a  class  as  controls  similar  matters  on 
the  continent  of  Europe,  the  rights  of  the  people  are  sought 
to  be  preserved  by  the  checking  and  balancing  of  sovereign 
and  independent  departments.  When  new  things  are  to  be 
done,  additional  statutes  are  enacted  and  more  boards  pro- 
vided. One  authority  will  make  an  improvement  and  an- 
other will  dig  it  up,  while  no  one  will  repair  it  because  the 
courts  have  not  decided  the  question  as  to  which  fund  shall 
be  drawn  upon  for  meeting  the  expense  in  cases  of  that  na- 
ture. Volumes  of  annual  reports  from  the  heads  of  the  sov- 
ereign departments  and  chiefs  of  the  multitudinous  bureaus 
into  which  they  have  been  sub-divided,  assure  a  confiding 


50  BRICK   FOR    STREET    PAVEMENTS. 

public,  that,  since  the  advent  to  power  of  the  present  incum- 
bent, the  affairs  under  his  control  have  been  conducted  upon 
strictly  business  principles,  thus  enabling  him  to  grant  more 
permits  and  file  a  larger  number  of  papers  than  had  ever  be- 
fore been  handled  by  similar  officers  in  a  corresponding 
length  of  time.  When  the  balance  of  power  between  po- 
litical parties  is  indefinite,  and  changes  in  official  stations 
become  so  frequent  as  to  make  employment  uncertain,  it 
is  sometimes  found  expedient  to  further  revise  the  stat- 
utes and  make  non-partisan  boards,  who  then  carefully  di- 
vide the  appointments  and  perquisites  between  contending 
parties,  accurate  data  for  the  making  of  such  partitions  be- 
ing always  available.  The  smaller  municipal  organizations 
copy  the  "  systems"  of  the  larger  ones. 

Under  such  regulations  no  very  considerable  amount  of 
"  engineering  "  is  required.  A  "  chief  engineer  "  of  suitable 
political  complexion  is  chosen  to  sign  the  necessary  papers, 
to  whom  matters  not  well  understood  by  other  parties  can  be 
referred  and  reported  upon,  and  who  can  be  blamed  when  it 
becomes  absolutely  necessary  to  locate  responsibility  some 
place,  and  who  is  willing  to  allow  officials  and  other  influ- 
ential parties  to  appoint  his  assistants,  clerks,  rodmen,  and 
superintendents.  Men  who  have  acquired  skill  and  experi- 
ence in  the  construction  of  works  under  different  regulations 
seldom  take  kindly  to  this  order  of  things,  and  the  field  is  left 
free  to  such  as  enjoy  the  surroundings.  Many  careful  and 
painstaking  men  are  engaged  in  city  work  who  would  make 
excellent  records  were  they  not  handicapped  by  the  regula- 
tions governing  them,  and  almost  the  entire  number  are 
like  the  parents  of  heroes,  "  poor  but  respectable."  Having 
little  at  stake  except  their  integrity,  that  is  manfully  cher- 
ished. Occasionally  an  erring  brother  may  fall,  but  he 
merely  drops  from  the  ranks  which  close  in  his  place.  The 


BRICK    FOR    STREET    PAVEMENTS.  51 

ammunition  of  the  enemy,  which  is  most  dangerous,  espe- 
cially to  those  of  limited  experience,  is  flattery.  Not  one 
person  in  ten  thousand  of  those  having  experience  upon 
public  works  would  ever  approach  an  engineer  with  money 
or  a  valuable  consideration  for  corrupt  purposes,  but  if  the 
insidious  agent  can  induce  him  to  believe  that  his  genius  is 
apparent  to  all,  and  that  the  world,  especially  the  official 
part  of  it,  will  soon  be  shouting  his  praises,  such  influences 
may  cause  the  young  man  to  make  himself  ridiculous.  But 
there  is  a  great  following  who  have  a  sufficient  knowledge 
of  surveying  to  enable  them  to  handle  field  instruments,  set 
out  work,  and  compute  quantities,  who  have  but  little  taste 
for  such  study  or  investigation  as  is  necessary  to  acquaint 
them  with  materials,  or  render  them  skillful  in  designing  or 
constructing  engineering  works;  and  there  appears  to  be  a 
greater  demand  for  these  persons  on  municipal,  than  upon  any 
other  class  of  public  works.  This  is  probably  because  they 
have  more  leisure  for  compiling  political  statistics  than 
others,  are  less  liable  to  have  bothersome  opinions  about 
how  things  should  be  done,  and  can  more  readily  discern 
the  grade  and  character  of  improvements  desired  by  those  in 
power  or  opposed  by  those  not  in  power,  which  is  usually  the 
same  thing ;  it  being  always  understood  among  municipal 
statesmen  that  an  election  or  appointment  to  office  confers 
upon  the  recipient  of  such  honor  all  the  necessary  knowl- 
edge and  experience  required,  not  only  to  choose  an  engineer, 
but  to  tell  him  what  to  do,  and  just  how  to  do  it.  Many  re- 
cruits are  obtained  from  those  estimable  young  men  annu- 
ally graduated  from  our  technical  schools  and  colleges.  The 
learned  professors  solemnly  announce  to  such  of  their  stu- 
dents as  have  pursued  certain  lines  of  study,  that  they  are 
now  civil  engineers.  The  young  men  very  properly  have 
great  confidence  in  their  teachers,  and  believe  what  is  told 


52  BRICK    FOR   STREET    PAVEMENTS. 

them  to  be  literally  true,  but  when  they  go  abroad  in  the 
world  and  learn  that  what  the  professors  really  meant  was, 
that  they  were  qualified  to  obtain  employment  upon  public 
works,  where,  by  continual  study  and  actual  practice,  they 
could  become  engineers;  the  shock  is  very  great,  many  never 
recover,  and  some  are  engaged  by  municipal  corporations. 
Such  as  do  recover  are  achieving  great  success  in  professional 
work. 

The  number  and  sovereignty  of  the  departments,  the 
uncertainty  of  the  laws  (for  no  one  dare  hazard  any  thing 
more  than  an  opinion  regarding  the  rule  of  action  prescribed 
by  a  statute  until  the  court  of  last  resort  has  guessed  at  its 
meaning),  and  the  strifes  of  contending  factions  have  pro- 
duced conditions  so  different  from  those  which  would  ap- 
pear to  be  proper  that  heroic  measures  may  be  required  to 
effect  desirable  changes.  Unless  the  people  at  large  can  be 
induced  to  look  upon  the  matter  of  municipal  government  as 
a  grotesque  absurdity  which  is  really  being  enacted  at  their 
expense,  as  it  is,  the  code  will  continue  to  be  enlarged  and  the 
Boards  multiplied.  When  they  induce  the  law-makers  to  re- 
peal the  thousand  and  one  statutes  which  now  exist,  and 
enact  a  plain,  concise  code  of  rules,  and  wot  amend  it,  which 
will  place  the  direction  of  public  works  under  a  single  de- 
partment, with  uniform  regulations  in  like  municipalities 
throughout  the  state;  placing  the  designing  and  manage- 
ment in  the  hands  of  a  corps  of  engineers  who  should  ac- 
quire position  and  promotion  by  the  record  of  their  achieve- 
ments, and  not  by  reason  of  race,  creed,  or  previous  con- 
dition of  partisan  servitude  or  influence,  and  who,  being  un- 
trammeled  as  in  the  world  at  large,  would  succeed  or  fail  by 
merit  alone,  the  principal  of  natural  selection,  or  the  survival 
of  the  fittest,  would  soon  place  the  direction  of  such  works 
in  systematic  order  under  competent  control.  Then  would 


BRICK   FOR    STREET    PAVEMENTS.  53 

streets  be  built  to  remain  undisturbed,  as  the  bottom  layers 
or  drains  and  pipes  would  first  be  put  down  and  carried  to 
property  lines,  tben  would  the  character  of  the  pavement  be 
adapted  to  the  uses  to  which  it  would  be  subjected.  Paving 
companies  \vould  construct  streets  and  guarantee  them  to 
remain  in  proper  form  and  repair  until  a  specified  traffic  ton- 
nage should  have  passed  over  them.  Manufacturers  would 
furnish  materials  under  like  conditions.  Order  and  uniform 
system  would  exist  where  chaos  now  reigns,  and  legislative 
interference  would  cease  to  trouble  executive  business. 

Probably  the  view  is  Utopian,  and  will  never  be  realized 
until  we  pace  those  golden  streets,  but  the  patching  remedies 
and  special  laws  continually  being  enacted  for  the  betterment 
of  evils  known  to  exist  are  only  adding  complications  to 
complex  affairs,  and  if  thinking  people  are  induced  to  direct 
their  attention  to  a  subject  of  such  universal  and  vital  inter- 
est, and  make  an  effort  in  unison  to  better  municipal  govern- 
ment as  applied  to  public  works  it  will  certainly  result  in 
some  good.  Politicians  and  bosses  will  undoubtedly  offer 
great  obstacles,  but  the  mere  absurdity  of  present  methods 
will  insure  a  change,  and  if  engineers  were  accorded  similar 
freedom  and  control,  with  such  responsibilities  and  oppor- 
tunities as  are  given  them  upon  other  works,  they  would  not 
ignore  so  inviting  a  field  as  that  presented  by  the  needed  im- 
provements in  these  matters. 

GENERAL  DISCUSSION  OF  PAVEMENTS. 

The  office  of  a  street  pavement  is  to  provide  a  wearing 
surface  which  shall  fulfill  the  following  conditions  : 

First.  It  must  present  a  secure  and  pleasant  footing  for 
animals. 

Second.  It  must  have  sufficient  smoothness  to  render 
traveling  in  carriages  agreeable,  and  traction  easy  and  as  nearly 


54  BRICK    FOR    STREET    PAVEMENTS. 

noiseless  as  is  practicable,  for  all  descriptions  of  wheeled  ve- 
hicles (excepting  those  provided  with  flanged  wheels). 

Third.  It  must  be  of  such  form  and  material  that  liquids 
falling  upon  it  will  quickly  flow  from  it  into  proper  conduits, 
and  must  furnish  no  permanent  lodgment  for  street  filth  of 
any  kind. 

Fourth.  It  must  be  capable  of  sustaining  without  change 
of  form,  any  and  all  loads  usually  transported  on  public 
highways. 

Fifth.  It  must  be  reasonably  durable,  both  as  against 
the  attrition  of  street  traffic,  and  the  destroying  or  dissolving 
action  of  the  elements. 

Sixth.  It  must  be  economical.  That  is  to  say,  sufficient 
comfortable  use  must  be  obtained  from  it  to  make  it  worth 
both  the  cost  of  construction  and  maintenance. 

Seventh.  It  must  be  capable  of  removal  and  replace- 
ment, or  repair  from  failure  at  reasonable  cost,  and  with 
materials  and  appliances  within  the  control  of  the  street  re- 
pairing department. 

A  study  of  these  conditions  at  once  reveals  the  reason 
why  the  "  paving  problem "  is  of  such  an  intricate  nature 
that  it  has  so  long  remained  unsolved,  as  well  as  a  cause  for 
so  many  unhappy  failures  in  its  attempted  solution. 

For  the  first  and  second  conditions,  the  dirt  road  in  good 
repair  stands  without  a  rival,  but  it  meets  no  other  require- 
ment, hence  its  use  is  restricted  to  race  tracks  and  country 
roads,  which  like  canals  are  only  navigable  when  the  weather 
conditions  are  favorable. 

For  the  second,  third,  and  fourth  conditions,  the  asphalt 
pavement  on  proper  foundation  appears  to  be  better  fitted 
than  any  other  that  has  come  into  such  general  use;  but 
many  persons  say  that  it  does  not  properly  meet  the  first  re- 


BRICK   FOR    STREET    PAVEMENTS.  55 

quirement,  criticise  it  severely  as  to  the  fifth  and  sixth,  and 
affirm  that  it  utterly  fails  to  meet  the  seventh. 

Stone  block  pavements  meet  the  first  requirement,  but 
indifferently ;  utterly  fail  in  the  second  and  third,  when 
properly  constructed ;  are  better  adapted  to  comply  with  the 
conditions  of  the  fourth,  fifth,  and  seventh,  than  almost  any 
other  description  of  city  street,  but  when  a  high  charge  for 
transportation  is  to  be  added  to  the  cost  of  preparing  the 
material,  they  fail  to  meet  the  sixth  condition. 

Wooden  block  pavements  meet  the  first,  second,  fourth, 
and  seventh  conditions  fairly  well,  when  made  of  suitable 
materials  well  combined ;  but,  as  they  have  been  built  in  this 
country,  have  signally  failed  to  meet  the  third  condition,  and 
have  fulfilled  the  fifth  and  sixth  but  very  indifferently. 

The  bowlder  or  cobble-stone  pavement  has  been  with  us 
so  long,  and  has  been  treated  so  badly,  that  familiarity  with 
it  has  bred  a  species  of  contempt  that  is  hard  to  overcome. 
It  has  become  popular  to  consider  it  an  all  around  failure, 
yet  it  meets  the  first  and  seventh  conditions  fairly  well,  and 
so  far  as  the  material  is  concerned,  it  stands  unrivaled  in  the 
fifth.  In  many  of  our  cities  where  horse  cars  have  been 
operated  for  the  past  twenty  or  thirty  years,  and  the  street 
railway  companies  are  required  to  maintain  the  pavements 
within  their  tracks,  the  bowlder  pavements  are  still  retained 
between  the  rails,  while  the  residue  of  the  streets  have  been 
paved  with  other  materials,  because  in  that  position  they  are 
said  to  meet  all  of  the  conditions  named,  excepting  possibly  the 
second  and  third,  better  than  any  other  substance  yet  offered 
for  the  wearing  surface  of  roadways.  This  saying,  however, 
does  not  appear  to  be  any  thing  more  than  an  expression  of 
opinion,  which  can  not  be  sustained  by  any  process  of  rea- 
soning. The  cobble-stone  can  be  given  no  definite  bearing 
on  any  foundation ;  it  can  not  be  held  in  position  by  any  bond 


56  BRICK  FOR  STREET  PAVEMENTS. 

that  can  be  given  it  in  construction.  It  does  not  present  a 
suitable  surface  for  vehicular  travel,  or  that  can  by  any  pro- 
cess be  kept  free  from  filth ;  yet  it  does  not  wear  out,  is  easily 
restored  if  loosened  from  its  place,  and  it  does  answer  very 
well  for  street  car  horses  to  travel  upon. 

Broken  stone  or  macadam  as  commonly  used,  of  mingled 
limestone  and  shale,  meets  none  of  the  requirements.  If, 
however,  it  is  clean  refractory  material,  properly  prepared 
and  combined  by  rolling,  it  fulfills  all  the  conditions  except 
the  third  (and  even  that  reasonably  well),  providing  the  traffic 
is  moderate,  and  the  repairing  is  promptly  and  efficiently 
done.  It  may  be  set  down  as  an  established  fact,  however, 
that  when  a  macadamized  street  is  dug  into  for  any  purpose 
that  it  is  never  properly  replaced. 

No  one  of  these  conditions  can  be  entirely  ignored,  yet 
it  is  obvious  that  no  pavement  yet  devised,  fully  meets  all  of 
them.  Could  the  first  be  ignored,  it  would  be  an  easy  mat- 
ter to  cover  street  surfaces  with  iron  or  steel  plates  that 
would  fully  meet  all  the  others,  but  plainly  this  can  not  be 
done.  The  surroundings  of  the  pavement  and  the  extent  and 
nature  of  the  traffic  to  which  it  is  to  be  subjected,  must  be 
considered  in  order  to  decide  which  of  the  conditions 
shall  be  allowed  to  determine  its  character.  The  first,  that 
of  furnishing  a  secure  and  reasonably  comfortable  footing 
for  animals,  can  in  no  case  be  ignored,  and  in  many  instances 
must  control  all  other  considerations.  Wherever  the  pave- 
ment is  to  be  used  as  a  thoroughfare  for  vehicular  traffic  at 
fair  rates  of  speed,  or  when  time,  pleasure  driving,  or  quiet- 
ness become  elements  of  importance,  then  the  first  and  sec- 
ond conditions  must  be  met,  and  other  features  may  or  may 
not  be  caused  to  yield  to  their  requirements.  But  the  pres- 
ervation of  life  and  health  is  the  essential  cause  of  business 


BRICK   FOR    STREET    PAVEMENTS.  57 

activity,  hence  the  third  condition,  that  of  maintaining  cor- 
rect sanitary  conditions,  should  never  be  neglected. 

To  those  at  all  familiar  with  street  construction,  it  is 
obvious  that  the  wearing  surface,  or  pavement  proper,  can 
not,  and  does  not  in  itself,  support  the  loads  brought  upon  it, 
but  that  it  more  or  less  successfully  resists  the  impact  and 
abrasion  incident  to  the  traffic,  and  transmits  the  weight  di- 
rectly to  the  bed  or  foundation  upon  which  this  surface  ma- 
terial has  been  placed.  It  follows,  therefore,  that  the  fourth 
-condition  can  be  met  by  any  description  of  paving  material 
which  has  sufficient  hardness  to  retain  its  form  under  the 
pressure  of  street  traffic,  by  merely  placing  it  on  a  properly 
prepared  foundation ;  and  further,  that  unless  the  pavement 
shall  be  placed  upon  a  bed  capable  of  sustaining  under  all 
conditions  the  loads  brought  upon  it,  the  surface  will  yield 
regardless  of  the  material  of  which  it  is  composed,  and  that 
this  condition  not  being  complied  with,  no  essential  feature 
of  a  good  street  surface  will  remain.  Failure  to  meet  this 
condition  is  the  error  most  commonly  committed  in  the  build- 
ing of  pavements.  In  this  latitude  the  winter  frosts  pene- 
trate to  a  depth  of  from  one  to  three  feet,  or,  when  not  acted 
upon  by  frost,  the  subsoil  drainage  is  seldom  so  thoroughly 
efficient  as  to  prevent  the  changing  of  the  ground  from  a 
firm  unyielding  soil  to  one  of  almost  complete  saturation, 
thus  materially  affecting  its  sustaining  power.  It  therefore 
follows  that  no  pavement  wlr.ch  is  to  be  subjected  to  a  heavy 
traffic  at  all  seasons  of  the  year  can  be  relied  upon  to  retain 
the  form  originally  given  it,  unless  the  foundation  or  bed 
upon  which  it  is  placed  shall  either  be  carried  below  the  ac- 
tion of  the  frost,  say  three  feet  or  more,  or  be  so  constructed 
as  to  distribute  the  weights  of  passing  loads  over  sufficient 
areas  to  enable  a  comparatively  weak  subsoil  to  sustain 
them.  The  deep  foundation  is  the  ancient,  and  undoubtedly 


58  BRICK    FOR    STREET    PAVEMENTS. 

the  most  durable  method,  having  apparently  been  the  ordi- 
nary practice  with  the  Romans,  but  the  distributing  coating 
is  far  more  economical,  and  hence  has  become  the  established 
modern  practice. 

Two  methods  are  in  vogue.  First,  to  drain  the  sub- 
roadway  as  efficiently  as  is  practicable,  grade  it  to  the  proper 
form,  compact  its  surface  by  rolling,  and  cover  it  with  a 
layer  of  mingled  broken  stone  and  gravel,  which  is  made 
smooth  and  firm  by  flooding  and  rolling  with  a  steam  roller ; 
the  layer  of  metal  being  from  six  to  twelve  inches  in  thick- 
ness, according  to  the  requirements  of  the  locality  or  the 
specifications.  On  this  layer  or  "  foundation  "  is  spread  the 
bed  of  sand,  in  or  upon  which  the  pavement  is  set.  Some- 
times broken  stone  alone,  and  again  gravel  only,  is  used  for 
the  bottom  course.  This  style  of  "  foundation  "  is  used  very 
extensively  for  all  descriptions  of  pavements  excepting  as- 
phalt. With  brick  pavements  the  practice  of  placing  a  layer 
of  bricks  flatwise  on  the  bed  of  sand,  covering  them  with  a 
thin  coating  of  sand,  and  paving  on  it  the  wearing  surface 
on  edge,  is  quite  common,  and  produces  what  is  called  the 
"two  course"  pavement.  Still  another  method  consists  in 
covering  the  layer  of  sand  with  tarred  boards,  upon  which 
the  sand  cushion  and  brick  on  edge  are  paved  herring-bone 
style,  producing  the  "Hale  Pavement."  In  this,  however,, 
the  broken  stone  is  generally  omitted,  the  boards  being  sepa- 
rated from  the  subsoil  by  from  four  to  six  inches  of  sand 
only.  These  expedients  tend  to  better  the  distribution 
of  the  weights  brought  upon  the  pavement,  and  have  the 
merit  of  economy  in  first  cost,  but  they  are  obviously  inade- 
quate except  where  the  subsoil  is  exceptionally  good  and  the 
traffic  very  moderate.  The  method  of  combination  is  quite 
defective.  When  gravel  is  used  that  is  free  from  loam,  it 
will  not  compact  under  the  roller,  and  if  it  does  contain 


BRICK    FOR    STREET     PAVEMENTS.  59 

loam  the  water  which  comes  from  the  subsoil,  and  percolates 
through  it,  is  liable  to  carry  the  soluble  substances  with  it 
down  the  gradients,  and  leave  the  pavement  unevenly  sup- 
ported. When  broken  stone  and  gravel,  or  broken  stone 
alone,  forms  the  foundation  course,  it  is  expected  to  be  por- 
ous, and  act,  to  some  extent,  as  a  subsoil  drain.  The  voids, 
however,  are  liable  to  become  the  receptacles  of  the  clay 
from  beneath,  which  is  brought  up,  or  rather  the  stones 
brought  down,  by  the  pressure  upon  the  pavement,  or  they 
will  be  filled  by  the  sifting  down  of  the  bedding  course  of 
sand,  caused  by  the  jar  of  the  travel,  and  this  escape  of  the 
sand  will  leave  the  blocks  unevenly  supported.  All  of  the 
varieties  described  in  this  first  method  are  extensively  used, 
and  are  made  more  or  less  expensive  and  durable,  or  cheap 
and  temporary,  as  they  are  carried  to  greater  or  less  depths, 
and  as  the  work  is  thoroughly  or  carelessly  done.  But  they 
are  so  constructed  that  natural  causes  would  alone  destroy 
them  in  a  comparatively  brief  space  of  time,  and  when  the 
forces  of  nature  are  aided  by  the  disturbances  to  which  the 
sub-grade  of  the  street  is  ordinarily  subjected,  and  the  traffic 
upon  the  pavement,  it  follows  that  the  life  of  such  a  founda- 
tion seldom  exceeds  the  duration  of  the  wearing  surface,  and 
the  failure  of  the  former  very  frequently  accelerates  the  de- 
struction of  the  latter. 

The  second  method  consists  in  preparing  the  subsoil  by 
grading  and  rolling  as  before  described,  and  placing  upon  it 
a  layer  of  hydraulic  cement  concrete  to  serve  as  a  founda- 
tion for  the  pavement.  For  equal  volumes,  the  cost  of  the 
concrete  is  about  three  times  that  of  the  broken  stone  or 
gravel;  but  from  one-half  to  two-thirds  of  the  amount  is 
required,  hence  the  expense  of  the  concrete  foundation  is 
one  and  a  half  to  twice  that  of  the  broken  stone  or  gravel. 
When  properly  made  and  undisturbed,  it  will  not  yield  to 


60  BRICK   FOR    STREET    PAVEMENTS. 

the  action  of  the  weather,  and  the  renewal  of  the  pavement 
need  extend  to  the  wearing  surface  only.  The  expense  of 
cutting  through  and  replacing  the  concrete  when  the  street 
must  be  opened  for  any  purpose,  is  much  greater  (perhaps 
two  to  three  times)  than  in  the  other  forms  of  foundation, 
but  such  work  can  be  done  without  serious  injury  to  the  re- 
mainder of  the  street ;  and  when  repairs  are  properly  made 
the  opening  of  the  pavement  and  its  foundation  is  less  in- 
jurious to  the  street  having  a  concrete  foundation  than  the 
one  that  has  it  not,  because  the  concrete  base  will  support 
the  pavement  over  small  cavities,  while  the  broken  stone  or 
gravel  will  sink  into  them. 

The  thickness  of  the  concrete  varies  with  the  require- 
ments of  the  traffic,  and  other  conditions,  from  four  to 
eight  or  more  inches.  The  ordinary  practice  is  to  use  nat- 
ural cement  in  its  composition,  and  make  the  coating  six 
inches  in  thickness  for  roadways  of  medium  traffic  without 
car  tracks.  The  condition  of  the  subsoil  should,  however, 
be  considered  in  determining  the  depth  of  concrete,  for 
where  it  is  soft  or  spongy,  or  trenches  are  to  be  spanned,  a 
greater  amount  will  be  required.  A  concrete  foundation  is 
an  absolutely  necessary  beginning  for  any  really  good  and 
durable  street  pavement,  and  even  for  work  of  medium 
character  and  price  it  is  economical.  Pavements  of  sheet 
asphalt  are  always  placed  on  concrete  foundations,  the  wear- 
ing surface  being  separated  from  the  cement  by  a  cushion 
coat,  ordinarily  about  half  an  inch  in  thickness. 

Stone,  asphalt,  wooden  block,  or  brick  pavements,  are 
usually  placed  on  a  layer  of  sand  from  one  to  two  inches  in 
thickness  over  the  concrete,  but  the  practice  regarding  the 
cushion  coat  is  by  no  means  uniform,  varying  from  an  actual 
bedding  of  the  blocks  in  the  cement  mortar  to  two  or  even 
three  inches  of  sand,  but  the  general  custom  in  this  country 


BRICK  FOR  STREET  PAVEMENTS.  61 

appears  to  be  in  favor  of  the  sand  cushion.  Convenience  in 
construction  and  repairs  and  the  theoretical  elasticity  of  sur- 
face being  in  favor  of  that  combination.  The  choice  of  the 
sand  to  be  used  is  of  more  than  ordinary  importance,  since  if 
it  contains  a  considerable  percentage  of  soluble  substances, 
or  is  alternately  coarse  and  fine  in  different  places,  displace- 
ment is  likely  to  occur,  and  the  pavement  will  become 
uneven. 

All  block  pavements,  whether  of  stone,  wood,  asphalt,, 
or  brick,  should  be  as  closely  placed  as  is  practicable,  and 
the  interstices  filled  with  a  non-absorbent  material.  Possibly 
a  narrow  spacing  may  be  required  on  gradients  paved  with 
sawed  wooden  blocks  to  furnish  footing  for  animals,  but  the 
wide  spacing  ostensibly  for  this  purpose  so  frequently  seen  in 
all  these  varieties  of  pavements  is  undoubtedly  bad  practice,, 
since  it  so  materially  reduces  the  resistance  of  the  material 
composing  the  wearing  surface,  facilitates  the  chipping  from 
the  angles,  and  produces  an  uneven,  noisy  street,  with  cavities 
to  receive  and  retain  filth. 

WHAT  SHALL  BE  SPECIFIED. 

The  writer  has  seen  no  specifications  for  brick  pavements 
which  either  clearly  or  fairly  describe  the  material  to  be  used, 
so  that  manufacturers  or  bidders  can  know  just  what  will  be 
required  upon  a  given  work.  The  majority  of  the  specifica- 
tions recite  that  "the  brick  to  be  used  must  be  hard,  free 
from  defects  of  any  kind,  manufactured  and  burned  espe- 
cially for  street  paving  purposes,  be  equal  in  all  respects  to 
the  sample  filed  with  the  proposal,  and  subject  to  inspection 
and  acceptance  or  rejection  by  the  engineer  or  inspector." 
With  our  present  knowledge  of  this  material,  this  phraseology 
may  be  accepted,  but  in  reality  it  specifies  very  little.  Its 
acceptance  or  rejection  by  an  engineer  is  ordinarily  regarded 


BRICK  FOR  STREET  PAVEMENTS. 

by  the  corporation  as  a  safeguard,  but  no  parties  entering 
into  a  contract  can  place  a  power  that  is  wholly  arbitrary 
and  undefined  in  the  hands  of  an  engineer,  who  is  in  reality 
the  executive  agent  of  one  of  the  parties.  Because  bricks 
have  been  manufactured  and  burned  especially  for  street 
paving  purposes,  does  not  necessarily  fit  them  for  such  use ; 
the  term  hard  is  an  indefinite  one,  and  without  stating  what 
constitutes  defects,  there  may  be  differences  of  opinion  as  to 
whether  or  not  they  exist  in  a  given  article  as  well  as  to  the 
equality  of  goods  furnished  with  sample  exhibited.  Even 
sample  paving  bricks  have  been  known  to  be  worthless  for 
street  paving.  The  characteristic  qualities  and  strength  of 
the  material  are  not  clearly  set  forth  as  they  should  be.  The 
power  to  accept  or  reject  is  left  undefined,  which  should 
never  be  the  case,  neither  manufacturer,  bidder,  nor  tax-payer 
should  be  bound  by  the  action  of  an  engineer,  unless  that  ac- 
tion shall  be  in  accordance  with  known  provisions  and  fixed 
rules.  With  the  hope,  therefore,  of  adding  something  to  the 
information  needed  for  bettering  specifications  in  this  re- 
spect, let  us  examine  our  work  as  tabulated. 

From  Tables  Nos.  1  and  8,  we  might  select  a  chemical 
composition  quite  suitable  for  the  purpose,  but  there  are  such 
wide  variations  in  clays  that  it  will  probably  be  advisable  not 
to  be  too  definite  in  specifying  ingredients.  Silica  may  con- 
stitute from  sixty  to  seventy -five  per  cent;  alumina,  from  fif- 
teen to  twenty-five  ;  iron,  from  five  to  ten;  while  lime  and 
magnesia  should  neither  exceed  two  per  cent;  and  the  al- 
kalies should  be  from  one  to  two  per  cent.  The  form  and 
proportions  in  which  these  ingredients  are  present,  and  the 
difference  in  results  obtainable  by  variations  in  methods  of 
manufacture  are  so  great,  that  it  will  evidently  be  better  to 
define  the  qualities  which  are  required,  and  leave  the  manu- 
facturer free  to  produce  them  in  his  own  way.  Lime  can 


BRICK  FOR  STREET  PAVEMENTS.  63 

be  readily  detected,  and  an  excess  of  that  ingredient  might 
properly  be  prohibited  by  the  specification. 

With  suitable  ingredients,  properly  combined  and  burned, 
the  percentage  of  absorption  will  be  small.  An  inspection 
of  Table  No.  2  shows  that  it  varies  greatly,  indicating  a  lack 
of  uniformity  in  results,  which  is  to  be  avoided,  or  failure  will 
result.  The  absorption  should,  therefore,  be  placed  at  the 
lowest  limit  which  can  be  designated  without  excluding  such 
bricks  as  are  known  to  have  withstood  other  tests  credit- 
ably. I  would  recommend  naming  two  per  cent  as  a 
maximum. 

Specific  gravity  depends  to  some  extent  on  the  density 
of  the  material,  and  should,  therefore,  be  as  high  as  is  ob- 
tainable with  this  material.  Two  and  one-tenth  might  be 
named  as  a  minimum,  with  credit  for  excess,  as  about  two 
and  three-tenths  is  attainable. 

The  crushing  strength  determined  from  two  inch  cubes, 
prepared  and  treated  as  set  out  in  describing  the  tests  shown 
in  Table  No.  3,  should  not  be  less  than  12,000  pounds  per 
•square  inch.  This  might  be  named  as  the  average  crushing 
strength,  the  limit  of  variation  of  any  sample  not  to  exceed 
twenty-five  per  cent  below. 

The  modulus  of  rupture,  as  determined  by  the  formula 
used  in  calculating  Table  No.  4,  from  tests  of  transverse 
•strength,  could  properly  be  fixed  at  1600. 

Tables  No.  5  and  7  would  indicate  that  unless  a  rather 
liberal  allowance  be  made  in  the  matter  of  abrasion  as  com- 
pared with  granite,  manufacturers  may  complain  that  many 
are  called  but  few  are  chosen.  One-third  of  the  competitors 
in  this  test  would  be  among  the  saved  by  placing  the  limit 
.at  two  and  two-tenths  times.  It  will  be  safe,  therefore,  to  say 
that  in  any  tests  for  determining  the  comparative  loss  of  the 
brick  under  abrasion  and  impact,  as  compared  with  Lithonia 


64  BRICK   FOR   STREET   PAVEMENTS. 

granite,  the  loss  in  weight  of  the  brick  shall  not  be  more 
than  two  and  one-fourth  times  that  of  the  granite. 

Uniformity  in  size  and  texture  appears  to  be  attainable, 
and  lack  of  it  produces  many  undesirable  difficulties.  Wide 
variations  iu  size  result  from  faulty  drying  and  burning.  We 
must  either  specify  how  the  drying  of  the  brick  and  the  tiring 
of  the  kiln  shall  be  done,  or  describe  what  we  want  as  the 
product  of  the  kiln,  and  insist  upon  getting  it.  In  the  pres- 
ent state  of  our  knowledge  the  safer  plan  will  be  to  name 
the  requirements  and  leave  the  manufacturer  to  wrestle  with 
details. 

The  amount  or  percentage  of  contraction  in  drying  and 
burning  varies  with  the  different  clays  from  one  to  twelve 
per  cent.  With  the  coal  measure  lire-clays  it  is  usually 
about  two  or  three  per  cent,  while  with  the  plastic  clays  and 
river  silt  it  is  very  much  greater.  Excessive  contraction 
is  obviated  to  some  extent  by  adding  to  the  mixture  ground 
burnt  clay  and  a  fusible  sand.  Unless  other  ingredients  are 
present  to  obviate  such  a  result,  these  components  are  liable 
to  produce  brittleness.  In  modern  down-draft  kilns  with 
clays  which  do,  and  should  contract  as  much  as  three  per 
cent,  rapid  firing  sometimes  produces  bricks  from  the  upper 
courses,  on  which  the  flame  acts  directly,  that  are  actually 
larger  than  the  molds  in  which  they  have  been  formed.  It 
follows  that  such  bricks  are  much  checked  and  cracked,  ren- 
dering them  unfit  for  use,  but  the  cause  is  apparent.  The 
contained  moisture  in  the  partially  dried  brick  is  expanded 
by  being  first  turned  into  steam,  and,  while  in  this  condition, 
the  outside  of  the  brick  is  fused,  thus  permanently  fixing  its 
exterior  form  and  dimensions,  except  as  modified  by  checks 
and  fire  cracks.  Other  bricks  in  the  kiln,  made  in  the  same 
molds,  will  be  shrunken  to  the  full  extent  of  their  contrac- 
tility, thus  producing  not  only  a  troublesome  variation  in 


BRICK   FOR    STREET   PAVEMENTS.  65 

size,  but  likewise  wide  differences  in  quality.  These  defects 
can  be  remedied  by  a  gradual  and  continuous  firing  that  will 
produce  and  permit  the  natural  amount  of  contraction 
throughout  the  kiln.  Absolute  uniformity  in  size  is  not 
practically  attainable,  but  a  much  nearer  approach  to  it  than 
is  now  common  can  be  reached  by  specifying  a  minimum  al- 
lowable deviation  and  rejecting  material  that  does  not  com- 
ply with  the  requirement.  I  would  suggest  two  per  cent 
as  the  maximum  allowable  variation  from  the  standard  di- 
mensions adopted. 

Assuming  that  the  clay  has  been  properly  ground  and 
mixed,  uniformity  in  texture  is  obtainable  only  by  conducting 
the  burning  in  a  suitable  manner,  continuing  it  to  a  sufficient 
degree,  and  no  longer,  and  then  allowing  the  kiln  to  cool 
down  without  permitting  drafts  of  cold  air  to  come  in  con- 
tact with  the  bricks  until  their  temperature  has  fallen  below 
the  boiling  point  of  water.  The  degree  to  which  the  firing 
should  be  extended  is  ordinarily  termed  "  complete  vitrifica- 
tion," but  would  appear  to  the  writer  to  have,  been  very  un- 
happily chosen.  To  "  vitrify  "  is  ordinarily  held  to  signify 
"  turning  into  glass  by  the  action  of  heat,"  which  is  not  the 
desired  result  in  this  case.  The  term  having  been  adopted  by 
common  consent,  the  meaning  which  defines  the  process 
must  be  given  it,  and  would  appear  to  be,  that  the  alkalies 
and  alkaline  earths  shall  form  vitreous  compounds  with  the 
iron  and  more  readily  fusible  silica,  so  as  to  give  the  brick  a 
dense,  uniform  texture,  obliterating  the  granular  appearance 
completely,  but  not  fusing  or  melting  the  brick  so  as  to  in- 
jure its  form  or  exterior.  This  result  is  obtainable  only  by 
progressive  firing  to  the  right  extent,  but  with  the  manufac- 
turer it  is  like  Major  Jones's  exercises,  the  fine  point  consists 
in  knowing  just  where  to  stop.  In  this  particular  feature 
the  fire-clays  are  claimed  to  be  superior  to  the  shales  and 
5 


66  BRICK   FOR    STREET    PAVEMENTS. 

silts.  The  latter  are  more  readily  fused  than  the  former,  and 
when  the  melting  point  is  reached  the  bricks  sometimes  lose 
their  form  and  melt  together.  To  avoid  danger  from  this 
source  sudden  cooling  is  resorted  to  and  the  product  is  ren- 
dered practically  worthless  by  the  brittleness  which  results 
from  such  a  course.  It  is  claimed  that  the  fire-clays  can  be 
held  at  a  sufficiently  high  temperature  to  produce  the  re- 
quired "  vitrification  "  without  danger  of  melting  together, 
and  hence  furnish  the  most  reliable  product  for  street  paving 
purposes.  Our  investigations  appear  to  point  to  the  conclu- 
sion, that  from  neither  clay  has  that  uniformity  of  product 
been  attained  which  is  desirable,  and  that  can  and  must  be 
made  before  reasonable  certainty  in  strength  and  durability 
can  be  assured ;  for  among  the  fire-clay  bricks  many  are 
found  that  show  scarcely  any  indications  of  fusion  or  "  vitri- 
fication "  at  all.  Many  more  that  are  but  partially  fused  or 
"  vitrified,"  the  exterior  portion  being  dense  and  non-ab- 
sorbent, while  the  interior,  marked  by  concentric  colored 
rings,  surrounds  a  central  portion  of  open  granular  texture, 
and  still  others  present  a  closed  metallic  or  granitic  texture 
throughout.  By  firing  and  annealing  in  a  proper  manner, 
uniformity  in  texture  without  brittleness  can  be  produced 
from  any  clay  that  is  suitable  for  the  manufacture  of  bricks 
for  street  paving.  These  qualities  should  be  specified,  and 
such  manufacturers  as  can  not  and  do  not  produce  them, 
should  not  find  sale  for  their  goods,  because  the  hopeful 
young  industry  will  soon  perish  or  be  relegated  to  the  smaller 
interior  cities  and  towns,  unless  these  essential  qualities  are 
produced.  It  may  be  asserted  that  such  requirements  will 
increase  the  cost  of  production.  If  need  be  let  it  be  so,  but 
such  as  furnish  the  required  product  will  find  a  continued 
and  increasing  demand  for  their  goods,  giving  a  permanent 
value  to  the  plant,  and  the  only  additional  expense  necessa- 


BRICK   FOR    STREET    PAVEMENTS.  67 

rily  involved  would   appear  to   be   more  time  and  care  de- 
voted to  the  burning  and  cooling. 

The  following  is  suggested  as  an  addition  to  the  specifi- 
cations, arid  as  more  knowledge  is  acquired,  further  revision 
may  be  necessary. 

"  The  bricks  or  blocks  to  be  used  for  paving  shall  be 
straight,  smooth,  and  free  from  checks  or  fire  cracks.  The 
corners  shall  be  rounded  to  a  radius  of  one-fourth  of  an 
inch.  In  size  they  shall  not  vary  more  than  two  per  cent 
in  any  dimension  from  the  standard  adopted  for  the  kind  of 
bricks  or  blocks  to  be  used.  When  broken,  the  fracture 
shall  be  smooth  and  straight,  not  conchoidal ;  and  the  text- 
ure of  the  block  shall  be  uniform  throughout,  and  not  gran- 
ular. The  amount  of  moisture  absorbed  when  tests  are 
made  either  with  the  whole  block  or  pieces,  shall  not  exceed 
two  per  cent  of  the  weight  of  any  sample  when  continuously 
immersed  for  three  consecutive  days.  ~No  bricks  will  be  ac- 
cepted which  contain  lime  or  other  soluble  substances  in 
sufficient  quantities  to  cause  spalling  or  pitting  of  the  sur- 
face when  soaked  in  water  for  three  consecutive  days  and 
then  exposed  to  the  air  for  a  corresponding  length  of  time. 

"  When  the  bricks  shall  have  been  delivered  upon  the 
roadway,  samples  may  be  selected  at  random  therefrom  for 
testing,  which  must  meet  the  following  requirements  :  The 
average  crushing  strength  of  two-inch  cubes  taken  from  any 
part  of  the  brick  shall  not  be  less  than  12,000  pounds  per 
square  inch. 

"  The  modulus  of  rupture  for  transverse  strength  shall 
not  be  less  than  1,600  pounds  when  calculated  by  the  for- 
mula, 

3  Wl 


68 


BRICK    FOR    STREET    PAVEMENTS. 


R  being  modulus  of  rupture,  W=load  in  pounds,  6=breadth, 
d=depth,  and  J=length,  all  in  inches. 

"  The  specific  gravity  shall  not  be  less  than  two  and 
one-tenth  when  determined  by  the  formula, 

W 

Specific  gravity=- 


x—  W 


Where  W=weight  of  specimen  freed  from  moisture  before 
immersion,  W=weight  of  same  after  seventy-two  hours' 
soaking,  and  W"=weight  of  same  in  water. 

"  In  any  test  for  determining  the  resistance  to  abrasion 
and  impact,  the  loss  of  the  brick  shall  not  exceed  two  and 
one-fourth  times  that  of  Lithonia  Georgia  granite  when 
subjected  to  like  test. 

"  The  material  shall  be  subjected  to  inspection  by  the 
engineer  placed  in  charge  of  the  improvement,  who  will  se- 
lect samples,  not  exceeding  live  in  number,  for  each  of  the 
tests  required  for  determining  absorption,  crushing  strength, 
transverse  strength,  and  abrasion  and  impact,  and  cause  the 
necessary  specimens  to  be  prepared,  the  tests  to  be  made, 
and  will  accept  or  reject  the  material  in  accordance  with  the 
results  of  such  trials.  An  allowance  of  twenty  per  cent  may 
be  made  for  variation  of  single  specimens,  but  the  average 
results  shall  be  in  accordance  with  the  provisions  herein  set 
forth,  or  the  material  must  be  rejected,  and  removed  at  the 
contractor's  expense.  The  tests  may  be  repeated  upon  the 
arrival  of  different  shipments,  as  frequently  as  may  be  nec- 
essary to  insure  the  acceptance  of  only  such  material  as  shall 
comply  with  the  provisions  of  this  specification." 

WHAT  HAS  BEEN  DONE. 

Bidders  were  informed  that  proposals  would  be  consid- 
ered for  any  of  the  varieties  of  brick  which  had  been  tested, 


BRICK  FOR  STREET  PAVEMENTS.  b(J 

but  that  such  as  showed  a  crushing  strength  of  less  than 
10,000  pounds  per  square  inch,  or  a  loss  in  the  rattler  test  of 
more  than  three  times  that  of  the  granite,  would  probably 
not  be  adopted.  When  the  bids  were  opened  it  was  found 
that  proposals  included  Nos.  5,  6,  13,  and  14  only,  and  the 
contracts  were  awarded  for  using  No.  14.  Subsequently  it 
was  decided  to  pave  about  300  or  400  feet  in  length  of  the 
south  end  on  the  south  contract  writh  Nos.  5  and  6,  and  a 
corresponding  length  on  the  south  end  of  the  north  contract 
with  No.  13,  which  has  been  done. 

The  form  given  to  the  roadway  is  shown  in  the  accom- 
panying sections.  Figure  1  showing  the  street  where  occu- 
pied by  street  railway  tracks,  and  figure  2  the  section  where 
no  tracks  were  placed.  Figure  3  is  a  full-sized  section  of 
the  rail  adopted.  This  was  placed  directly  on  the  tie,  or 
rather  on  a  bearing  plate  but  three-eighths  of  an  inch  in 
thickness,  spiked  directly  to  the  tie  ;  each  alternate  plate 
having  an  outside  brace  to  aid  in  holding  the  rails  to  guage, 
thus  obviating  the  necessity  of  using  any  other  appliance  to 
effect  that  purpose.  In  surfacing  tracks,  the  rail  of  each 
track  nearest  the  center  line  of  the  street  was  placed  one 
inch  higher  than  the  opposite  rail  of  the  same  track.  Tem- 
plates were  used  for  forming  the  sand  bed  on  which  the 
pavement  was  placed.  Figure  4  shows  that  used  for  the 
the  central  space  between  tracks ;  figure  5  the  one  for  the 
tracks,  and  figure  6  that  for  the  spaces  between  car  tracks 
and  curb-stone.  It  will  be  noticed  that  the  template  used 
at  the  sides  differs  slightly  from  the  form  specified  in  the 
cross-section  of  street,  but  this  variation  is  believed  to  be  a 
betterment,  being  in  the  nature  of  a  camber  against  the 
greater  weight  of  traffic,  and  tending  to  confine  the  water 
near  the  curb. 

Stakes  were  given  for  the  alignment  and  grade  of  tracks, 


70 


BRICK  FOR  STREET  PAVEMENTS. 


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BRICK   FOR   STREET    PAVEMENTS.  73 

and  where  tio  tracks  were  laid,  levels  were  given  from  the 
curbs  for  forming  the  concrete  and  bed  for  the  pavement. 
The  resulting  form  of  street  has  less  crown  than  is  usually 
given  to  streets  paved  with  brick,  but  it  is  pleasing  to  the 
eye,  the  entire  surface  is  available,  and  it  is  believed  that  it 
will  be  more  durable  than  it  would  be  were  the  cross  grades 
steeper,  because  there  is  no  influence  tending  to  concentrate 
the  traffic  in  lines  on  any  portion  of  the  roadway. 

The  form  of  rail-head  will  be  observed  to  be  almost 
identical  with  that  recommended  so  urgently  in  my  report 
of  May,  1889,  but  the  base  of  rail  and  general  construction 
of  track  is  materially  different.  The  ties  are  of  white  oak, 
5"  x  7",  placed  three  feet  between  centers,  excepting  at  rail- 
joints,  where  the  ties  are  double  width.  The  joints  are 
strong;  splice  bars  being  24"  in  length,  fitting  snugly  against 
base  and  head  of  rails  and  being  secured  by  six  one-inch 
bolts.  The  pocket  or  space  between  base  and  head  of  rail 
was  filled  with  a  fine  concrete  or  cement  mortar,  smoothed 
with  a  trowel  to  make  vertical  faces  against  which  the  p^v- 
ing  was  set.  The  concrete  was  driven  under  the  ties  with 
tamping  bars,  so  as  to  secure  a  depth  of  three  inches  of  this 
material  on  which  they  should  rest.  For  the  heavy  motors 
and  high  speeds  now  used  on  electric  roads,  this  depth 
should  be  increased,  but  when  no  part  of  the  expense  of stich 
foundation  is  borne  by  the  railway  company,  it  appears  un- 
just to  increase  the  cost  of  a  street  improvement  solely  for 
that  company's  benefit.  When  grants  to  street  railway  com- 
panies are  made  for  the  use  of  such  power,  they  should  con- 
tain provisions  for  placing  the  tracks  on  suitable  foundations, 
in  order  that  stability  may  be  obtained,  and  pavements  not 
be  endangered  from  such  causes. 

The  form  of  curb  adopted,  and  the  manner  of  setting  it, 
were  very  much  criticised  whett  the  plans  were  first  submit- 


74  BRICK   FOR   STREET    PAVEMEN7TS. 

ted,  as  it  is  a  radical  departure  from  what  has  been  consid- 
ered established  city  practice,  but  the  innovation  is  now  very 
generally  conceded  to  be  an  improvement.  Bottoms  of  curb 
stones  were  not  required  to  be  dressed  or  pitched  to  a  line, 
and  no  spalling  away  required  where  variations  from  speci- 
fied dimensions  did  not  exceed  two  or  three  inches.  There 
was  a  disposition  to  reject  pieces  varying  from  the  prescribed 
dimensions  when  the  depth  at  any  point  was  less  than  the 
specified  depth.  To  avoid  having  such  pieces  rejected,  the 
quarrymen  soon  learned  to  confine  the  variance  to  excess 
only,  which  resulted  in  getting  stones  of  an  average  depth 
of  sixteen  rather  than  fourteen  inches.  Inasmuch  as  they 
had  been  informed  that  pitching  to  a  line  would  not  be  in- 
sisted upon  where  stones  were  broken  to  within  two  inches- 
of  prescribed  dimensions,  the  result  was  a  rather  detrimental 
excess  of  stone.  The  tile  drain  was  generally  placed  twenty- 
four  inches  below  the  top  of  curb  and  covered  with  sand,  the 
top  of  which  was  smoothed  off  at  just  twenty  inches  below 
top  of  curb,  then  a  foundation  of  concrete  about  four  inches 
in  depth  was  placed,  upon  which  the  curb-stones  were 
blocked  in  position,  and  the  residue  of  the  concrete  required 
by  the  plan  tamped  under  and  filled  about  them.  This  form 
of  curb  should  reach  to  and  be  bedded  in  the  concrete ;  ex- 
cessive depth  of  stone  merely  serves  to  more  nearly  cut  the 
concrete  off  and  deprive  the  curb  of  efficient  support.  If 
exact  dimensions  are  to  be  insisted  upon,  curbs  should  be  cut 
to  them  on  all  sides,  but  that  is  obviously  a  useless  expense. 
There  was  almost  constant  irritation  regarding  the  rela- 
tive elevation  of  the  pavement  and  the  rails  of  the  car  tracks. 
The  language  of  the  specifications  upon  this  point  is  the 
following:  "  The  bricks  or  blocks  will  be  paved  adjacent  to- 
the  rails  in  such  manner  that  when  rammed  and  rolled,  as 
herein  before  specified,  the  surface  of  the  pavement  will  not 


BRICK    FOR    STREET    PAVEMENTS.  75 

vary  more  than  one-fourth  (i)  of  an  inch  from  that  of  the 
steel  rails,  and  never  be  below  them."  For  work  to  be  done 
under  similar  circumstances,  the  last  clause  should  read,, 
"and  never  be  above  them,"  because,  for  some  undefinable 
reason,  this  was  construed  to  mean  that  the  pavement  was 
intended  to  be  a  quarter  of  an  inch  higher  than  the  raiL 
Excessive  ramming  would  drive  the  bricks  down  along  the 
lines  of  rails,  but  there  was  no  method  of  raising  them  ex- 
cept to  take  them  up  and  put  in  sand.  After  being  required 
to  raise  a  few  patches  upon  the  mistaken  idea  that  the  bricks- 
were  too  low,  the  pavers  would  raise  the  templates,  keep  the 
bed  high,  and  endeavor  to  escape  censure  by  ramming  heav- 
ily along  the  rails,  resulting  in  getting  the  surface  of  the 
pavement  about  one-fourth  of  an  inch  higher,  as  compared 
with  the  rails,  than  it  should  be.  This  will  very  greatly  in- 
crease the  wear  upon  the  bricks  adjacent  to  the  tracks,  en- 
hance the  tendency  of  the  pavement  to  rise,  or  the  bricks  to 
"  pop  out "  when  shaken  by  passing  cars,  lessen  the  tractive 
force  of  the  motors,  add  to  the  labor  of  keeping  the  rails- 
clean,  and  lead  vehicles  to  follow  these  incipient  grooves 
along  the  car  tracks,  which  the  grooved  rail  was  intended  to 
discourage.  No  mention  need  be  made  in  this  connection  of 
the  causes  which  produced  this  result,  since  it  can  not  now 
be  obviated.  Where  the  directions  of  an  engineer  carry 
with  them  the  clear,  undisturbed  force  which  such  orders 
should  have,  results  are  seldom  variable,  and  if  they  are  un- 
satisfactory the  responsibility  is  not  a  divisible  quantity. 
When  the  traffic  tonnage  is  compared,  it  will  be  found  that 
the  eight  inches  of  steel  in  the  two  car  tracks  carries  so 
much  more  than  an  equivalent  width  of  brick,  that  it  is  fair 
to  assume  that  the  rails  will  be  lowered  almost,  if  not  en- 
tirely, as  rapidly  as  the  bricks  will  be  worn  down,  so  that 
there  never  is  a  time  when  a  good  reason  can  be  given  for 


76  BRICK   FOR    STREET     PAVEMENTS. 

not  making  the  surface  approximate  as  closely  as  is  practi- 
cable to  a  uniform  plane.  There  is  a  much  nearer  approach 
to  this  result  on  Main  avenue,  as  it  is,  than  is  found  in  the 
average  city  street,  and,  taken  as  a  whole,  it  is  believed  to 
be  at  this  time  the  most  comfortable  as  well  as  the  hand- 
somest drive  which  contains  a  double  track  street,  railway 
line  in  the  State  of  Ohio,  and  the  street  car  service  in  the 
village  is  believed  to  be  as  efficient,  and  approach  as  nearly 
to  the  ideal  rapid  transit,  as  has  yet  been  attained  by  any 

suburb. 

THE  MATRIX. 

One  condition  appears  to  be  essential  in  the  construction 
of  brick  or  stone  block  pavements,  which  are  to  be  either 
durable  or  smooth,  and  that  is,  to  give  each  brick  or  block 
such  efficient  support,  and  to  bind  all  so  firmly  together, 
that  passing  loads,  whatever  their  weight,  shall  cause  no  move- 
ment of  the  separate  pieces  upon  the  foundation  or  each  other. 
In  brick  pavements  on  a  sand  cushion  this  result  can  only  be 
secured  by  completely  filling  all  joints  with  a  cementing  sub- 
stance. On  this  work  the  substance  used  was  coal-tar,  or, 
as  it  is  generally  called,  paving  cement.  Care  was  taken  to 
keep  the  surface  clean  during  the  setting  and  ramming  of 
the  bricks,  to  sweep  all  spalls  or  rubbish  from  the  surface  in 
advance  of  the  tar-pourers,  and  to  project  into  each  joint  a 
stream  of  tar  at  a  high  temperature  that  should  penetrate 
and  fill  every  cavity  from  the  sand-bed  to  the  surface.  A 
second  pouring  or  "plugging"  always  followed  the  first, 
in  order  to  fill  such  joints  as  allowed  the  tar  to  sink  below 
the  surface  to  any  perceptible  extent,  and  then  the  surface 
was  covered  with  clean,  sharp  sand.  Practically,  the  best  py- 
rometer for  determining  the  temperature  of  the  tar  is  its 
appearance.  Pouring  should  not  be  allowed  unless  it  is 
smoking  hot  and  perfectly  liquid.  To  assert  that  every  one 


BRICK  FOR  STREET  PAVEMENTS. 

of  the  millions  of  crevices  was  completely  filled  is  not  in- 
tended, since  such  a  result  would  hardly  be  within  the  bounds 
of  possibility,  but  in  every  instance  where  bricks  were  taken 
out  after  the  tar-pouring  had  been  done,  they  were  found  to 
be  solidly  united  by  the  tar,  and  hardly  a  square  inch  of 
surface  could  be  discovered  that  had  not  been  covered  by  it. 
Great  care  is  necessary  in  doing  the  tar-pouring,  as  the 
smearing  of  tar  over  the  surface,  leaving  the  spaces  beneath 
unfilled,  is  much  worse  than  omitting  it  entirely,  as  its 
presence  will  prevent  the  sand  covering  from  penetrating 
until  the  traffic  shall  have  rendered  the  surface  uneven.  The 
sand  used  for  covering  the  pavement  should  be  absolutely 
free  from  loam.  It  should  be  sharp  and  gritty.  There 
should  be  a  marked  variation  in  size  of  the  particles  of 
which  it  is  composed,  and  they  should  be  sharp  and  angular, 
not  rounded.  One-fourth  of  an  inch  in  depth  is  an  abund- 
ance in  quantity,  and  it  should  be  evenly  spread  as  soon  as 
the  tar-pouring  has  been  completed,  so  that  when  the  tar 
sinks  into  the  joints,  if  it  does  sink,  it  will  carry  the  grit 
with  it. 

A  cement  grouting  is  coming  into  general  use  in  place 
of  the  coal-tar  filling,  which  is  preferred  by  many  engineers, 
from  the  fact  that  hot  weather  renders  the  tar  so  nearly  fluid 
that  it  flows  toward  the  lower  levels,  and  leaves  the  higher 
points  unfilled.  If  made  of  Portland  cement,  and  thoroughly 
slushed  into  all  crevices,  the  cement  would  give  satisfactory 
results.  For  a  comparison  between  the  two  materials  these 
conditions  exist.  With  the  coal-tar,  however  much  it  may 
be  melted  by  heat,  it  reunites  and  becomes  firm  again  so 
soon  as  the  temperature  falls ;  while  with  the  cement,  should 
the  bond  once  be  broken  from  any  cause,  it  never  reunites. 


78 


BRICK   FOR   STREET   PAVEMENTS. 


WHERE  SHOULD  BRICK  BE  USED  FOR  STREET  PAVEMENTS. 

Statements  made  in  preceding  paragraphs  have  indicated 
that  the  brick  pavement  will  not  have  the  durability  in  lo- 
calities where  street  traffic  is  greatly  concentrated,  that 
would  be  obtained  from  the  greater  mass,  and  superior  re- 
sistance to  wear  of  granite  blocks.  Are  bricks,  then,  a  suit- 
able paving  material  in  any  locality?  Undoubtedly  they 
are,  when  they  do  not  absorb  more  than  two  or  three  per 
cent  of  their  weight  of  moisture,  and  will  withstand  the  wear 
of  the  street  traffic  for  a  reasonable  length  of  time.  In  any 
city  having  a  population  less  than  100,000,  there  are  few,  if 
any,  streets  upon  which  the  volume  of  traffic  is  concentrated 
to  such  a  degree  as  to  endanger  a  well  constructed  brick 
pavement  for  many  years.  Upon  streets  mainly  occupied  by 
residences,  where  reasonable  quiet  and  correct  sanitary  condi- 
tions are  indispensable,  brick  are  in  every  way  superior  to  stone 
block  pavements,  and  in  durability;  when  the  cost  of  mainte- 
nance is  considered  are  superior  to  asphalt,  because  the  latter 
form  of  pavement,  when  not  used  at  all,  will  undergo  changes 
which  will  render  it  brittle  and  practically  useless,  whereas 
the  brick  will  not  be  similarly  affected.  This  change  in  asphalt 
from  exposure  is  probably  not  thoroughly  understood,  but  it 
is  acknowledged  to  exist,  and  is  the  principal  cause  of  ex- 
pense in  maintaining  pavements  made  of  it.  Sheet  asphalt 
is  not  worn  from  a  pavement  by  the  traffic  to  such  an  extent 
that  it  would  require  renewal  during  the  lifetime  of  a  gen- 
eration, but  it  is  pressed  out  of  position  by  the  traffic,  or 
rendered  brittle  by  changes  in  its  composition.  Probably 
two-thirds  or  more  of  the  cost  of  maintenance  is  due  to  the 
latter  cause,  which  action  is  believed  to  be  retarded  rather 
than  accelerated  by  the  traffic  upon  it.  In  brick  pavements 
the  action  of  the  weather  will  affect  the  combining  materials, 


BRICK   FOR   STREET    PAVEMENTS.  79 

not  to  an  appreciable  extent  the  bricks  themselves  unless 
it  be  defective  ones  which  can  readily  be  removed  and  re- 
placed. It  follows,  therefore,  that  the  cost  of  maintenance 
of  brick  streets,  when  made  of  good  material  on  permanent 
foundation  and  subjected  to  moderate  traffic,  will  be  less  than, 
that  of  any  other  form  of  pavement,  excepting  only  granite 
blocks.  Brick  is,  therefore,  a  suitable  material  to  be  used 
upon  a  very  large  percentage  of  all  paved  streets,  for  granite 
blocks  are  in  no  way  fitted  for  use,  either  upon  residence 
streets  or  upon  such  avenues  as  lead  to  residence  districts, 
where  the  driving  is  at  fairly  high  speed,  and  should  be  done 
with  safety  and  comfort.  This  brings  brick  into  direct  com- 
petition with  asphalt  as  a  paving  material,  and,  while  it  must 
be  admitted  that  the  asphalt  paving  companies  are  deserving 
of  great  credit  for  their  efforts  and  success  in  producing  good 
streets,  it  must  also  be  granted  that  persevering,  honest  com- 
petition will  result  in  public  benefit  if  conducted  on  correct 
principles.  The  indiscriminate  careless  use  of  brick  as  a 
paving  material  will  result  beneficially  to  the  asphalt  inter- 
est, and  disastrously  to  the  brick  manufacturers,  but  the  con- 
struction of  good  brick  streets  will  create  an  increasing  de- 
mand for  them.  And  while  it  may  not  seriously  injure  the 
business  of  the  asphalt  companies,  it  will  have  a  tendency 
to  lower  both  the  first  cost  and  the  maintenance  of  streets 
constructed  by  them. 

Many  streets  are  now  opened  and  paved  in  a  more  or  less 
expensive  manner,  where  no  such  outlay  should  be  made,  as 
the  work  is  totally  wrecked  in  the  subsequent  laying  of  gas 
and  water  mains,  constructing  sewers,  and  making  connec- 
tions with  such  lines.  Common  sense  would  indicate  that 
the  order  of  work  should  be  reversed  ;  that  a  subgrade  should 
be  made ;  all  underground  conduits  completed  and  connec- 
tions therewith  carried  to  property  lines  ;  the  surface  then 
covered  with  a  coating  of  gravel  or  broken  stone  and  gravel, 


80  BRICK    FOR    STREET    PAVEMENTS. 

which  should  be  used  as  a  roadway  until  trenches  had  be- 
come firm,  and  this  metal  would  then  remain  on  which  to 
place  the  foundation  for  the  permanent  pavement.  Were 
this  order  of  work  insisted  upon  in  opening  new  streets  an 
immense  saving  would  be  effected.  In  repaying,  the  work 
should  be  done  in  the  same  order,  suiting  the  manner  of  ex- 
ecuting it  to  the  necessities  of  the  case,  and  the  control  of 
all  of  it  should  be  under  a  single  authority,  with  plans  emi- 
nating  from  one  source.  When  the  traffic  upon  any  street, 
or  the  use  of  such  street  demanded  it,  let  such  a  pavement 
be  laid  as  is  suitable  to  meet  the  requirements  of  the  case, 
and  when  it  has  been  put  down,  keep  it  clean,  in  good  re- 
pair and  open  to  public  use.  Upon  a  very  large  percentage, 
probably  more  than  two-thirds,  of  the  paved  streets  in  the 
larger  cities,  and  upon  nearly  all  streets  requiring  pavements 
in  the  smaller  cities  and  towns,  brick  will  be  found  to  be  a 
suitable  material  to  compete  with  other  substances  for  street 
paving.  This  is  not  saying  that  brick  is  the  "  coming  pave- 
ment." On  the  contrary  brick  has  got  here.  If  used  prop- 
erly it  will  stay  and  will  be  a  standard  material  for  paving 
streets.  In  the  great  cities  where  traffic  is  heavily  concen- 
trated and  little  attention  is  given  to  the  roaring  of  the  pass- 
ing current,  it  will  never  supplant  the  granite  block ;  in  the 
park  drive,  the  clean  rolled  surface  of  hard  finely  broken 
stone  will  not  give  way  to  it ;  the  fine  avenue,  where  neat- 
ness, order  and  style  must  be  maintained,  will  still  be  pa\ed 
with  asphalt,  but  it  is  to  be  hoped  that  the  noisome  rotting 
wooden  block,  and  the  rattling  filthy  cobble-stone,  will  not 
remain  to  annoy  every  sense  of  propriety  and  slowly  murder 
both  innocent  and  guilty  by  their  noxious  exhalations. 

Upon  nine-tenths  of  the  paved  streets  occupied  by  resi- 
dences, retail  stores  or  office  buildings,  it  would  be  an  error 
almost  criminal  to  put  down  the  noisy,  untidy  granite  block, 
and  it  would  be  still  worse  to  use  the  wooden  block,  as  it  is 


BRICK    FOR    STREET    PAVEMENTS.  81 

ordinarily  laid  in  this  country,  while  a  good  brick  pavement 
would  be  quiet,  can  be  kept  very  clean,  and  in  nearly  all  such 
cases  would  last  almost  a  lifetime,  with  a  minimum  expense 
for  repairs. 

MAINTENANCE. 

The  ordinary  practice  regarding  the  maintenance  of 
street  pavements  appears  to  be  at  variance  with  established 
methods  in  any  other  similar  thing.  When  a  line  of  railway 
has  been  constructed  it  is  placed  in  charge  of  the  department 
of  maintenance  of  way,  and  is  kept  in  proper  condition  for 
use.  When  a  street  has  been  improved  the  gay  and  festive 
plumber,  singing  as  he  toils,  is  legally  permitted  to  dissect  its 
vitals ;  licensed  sewer-tappers  will  disembowel  it  upon  the 
authority  of  a  sovereign  department ;  street  railway  compa- 
nies will  dig  it  up  to  adjust  their  tracks  ;  the  water  depart- 
ment will  probe  it  to  rearrange  their  connections,  and  £>;as 
companies  will  carve  it  to  erect  their  lamps.  Each  will  re- 
place the  disturbed  material  in  his  own  way,  and  the  street- 
cleaning  department  will  haul  away  such  as  remains  loose 
upon  the  surface.  In  the  meantime  no  one  looks  for.  or 
remedies  defects  in  their  incipiency,  the  street  having  just 
been  paved  is  supposed  to  require  no  attention,  and  so  long 
as  it  remains  passable  without  danger  to  life  and  limb,  is  ;,iot 
repaired.  If  a  drain  becomes  clogged  no  one  knows  any- 
thing about  it  until  the  owners  of  the  inundated  properties 
file  claims  for  damages,  which  are  promptly  referred  to  the 
engineer  and  solicitor.  If  vehicles  are  wrecked  or  animals 
crippled  the  claims  filed  by  owners  go  to  the  legal  depart- 
ment, and  not  until  the  street  has  been  absolutely  destroyed 
will  it  receive  any  attention  from  the  repairing  department. 
If  it  should  happen  to  have  been  constructed  under  the 
supervision  of  officials  of  an  opposite  political  complexion 
from  those  now  repairing  it,  money  will  be  lavished  upon  it 
to  show  how  utterly  rotten  and  useless  were  the  works  con- 
C 


82  BRICK    FOR    STREET    PAVEMENTS. 

structed  at  enormous  expense  by  the  other  party.  Should  it 
be  some  of  their  own  work,  it  will  be  easy  to  show  that  it 
was  honestly  constructed,  but  was  ruined  by  the  actions  of 
other  sovereign  and  independent  departments. 

Imagine  the  effect  of  placing  railways  under  the  control 
of  half  a  dozen  independent  boards  with  no  executive  head, 
their  revenues  separated  into  distinct  funds  with  sovereign 
boards  to  disburse  them,  each  caring  mainly  that  its  minutes 
shall  record  resolutions,  ordinances,  or  references  in  proper 
sequence  and  due  form ;  so  worded  as  to  guard  the  rights 
and  actions  of  the  board  as  a  body,  and  show  that  various 
matters  were  considered,  and  would  be  acted  upon  when  some 
other  department  had  done  something  else.  Think  of  any 
corporation  conducting  any  business  enterprise  upon  such 
methods,  and  cease  to  wonder  why  pavements  are  not  kept 
in  repair. 

During  the  first  years  of  the  life  of  a  pavement  it  should 
be  carefully  watched,  and  the  beginnings  of  evil  to  it  should 
be  checked,  just  as  a  new  line  of  railway  will  require  a 
heavier  force  of  section  men  than  one  that,  having  been 
properly  maintained,  has  been  longer  in  use.  Expensive  re- 
newals may  be  needed  as  portions  of  the  structure  become 
worn  by  use,  but  care  and  watchfulness  are  of  greatest  use 
upon  new  work.  And  this  is  just  as  true  of  streets  as  it  is 
of  any  like  constructions.  Contracts  for  street  construction 
frequently  contain  provisions  requiring  the  constructor  to 
maintain  his  work  for  periods  of  time  varying  from  one  to 
five  or  more  years,  but  the  meaning  usually  given  this  clause 
by  the  contractor  is,  that,  at  the  expiration  of  the  time 
named  he  shall  make  such  repairs  of  the  portions  of  his 
work  which  have  not  been  dug  up  in  the  interval  by  some 
other  party  as  may  be  designated,  and  received  the  retained 
percentage.  There  is  uncertainty  about  this  provision  re- 
maining in  force  for  any  considerable  length  of  time.  En- 


BRICK    FOR    STREET    PAVEMENTS.  83 

terprising  attorneys  may  argue  that  assessments  should  be 
made  for  the  cost  of  construction,  and  that  the  expense  of 
maintenance  should  not  be  assessed,  but  borne  by  the  corpora- 
tion, and  no  one  can  tell  what  the  court  will  say  until  it 
speaks  in  deciding  the  case  as  then  presented.  An  efficient 
force,  under  experienced,  skillful  direction,  employed  in  the 
inspection  and  maintenance  of  streets  would  appear  to  be  an 
absolute  necessity  in  every  municipality.  If  such  an  organi- 
zation exists  in  any  American  municipality,  it  has  published 
no  report  of  its  services  to  date.  If  existing  regulations  can 
not  be  bettered,  then  our  form  of  government  as  applied  to 
municipalities  is  a  failure. 


WHAT  is  IN  A 
The  title  brick,  as  applied  to  clay  products  used  for  street 
paving,  would  appear  to  the  writer  as  a  misnomer.  The 
name  ordinarily  conveys  to  the  engineer  or  builder  the  idea 
of  a  brittle  porous  substance,  so  hungry  for  moisture  that  it 
must  be  saturated  before  being  laid  in  mortar,  solely  for  the 
preservation  of  the  mortar,  so  brittle  that  unless  combined 
in  masses  it  has  little  strength,  and  in  no  way  suited  to  with- 
stand the  attrition  or  abrasion  of  street  traffic.  When  peo- 
ple propose  to  use  such  a  substance  for  paving  streets,  the 
idea  is  ridiculed,  and  they  must  explain  that  they  are  not 
using  building  brick,  but  an  entirely  different  substance, 
manufactured  by  brick  makers,  and  in  explaining  the  matter 
use  is  made  of  the  other  unhappy  term,  "  vitrified  brick." 
The  only  clay  product  suitable  for  use  in  paving  streets  re- 
sembles a  tile  in  more  respects  than  it  does  a  brick,  and  had 
the  name  tile  been  chosen  in  the  place  of  brick  a  more  cor- 
rect idea  would  have  been  conveyed.  The  first  having  gone 
forth,  however,  it  may  be  expedient  to  concur  in  the  usual 
practice,  but  it  will  always  be  necessary  to  bear  in  mind  that 
brick  as  used  in  street  paving  is  a  substance  radically  differ- 
ent from  brick  as  used  in  any  other  connection. 


84  BRICK  FOR  STREET  PAVEMENTS. 

SIZE  OF  PAVING  BRICK. 

A  glance  at  the  tables  giving  dimensions  of  specimens 
reveals  the  curious  fact  that  hardly  any  two  manufacturers 
make  bricks  of  the  same  size.  One  of  the  first  steps  to  be 
taken  by  manufacturers  should  be  the  adoption  of  a  stand- 
ard size  for  street  paving  bricks.  Obviously  their  preference 
would  be  to  make  blocks  of  about  the  same  dimensions  as- 
building  bricks  for  both  uses.  When  they  make  paving 
blocks  only,  and  sell  by  the  square  yard,  their  interest  will  lie 
in  the  direction  of  increased  thickness  and  diminished  width. 
A  large  majority  of  manufacturers  supply  material  for  brick 
masonry  as  well  as  for  paving,  and  can  assort  their  output 
without  material  loss,  thus  enabling  them  to  supply  better 
goods  for  paving  when  they  are  required  so  to  do,  without 
suffering  the  entire  loss  of  the  value  of  such  as  may  be  re- 
jected. This,  from  the  manufacturers'  standpoint,  is  the 
greatest  argument  in  favor  of  making  the  dimensions  of 
paving  the  same  as  building  brick. 

The  users  side  of  the  question  should  be  considered. 
The  width  of  the  brick  or  block  forms  the  thickness  or 
depth  of  the  pavement.  This  should  not  be  less  than  four 
inches.  If  made  much  in  excess  of  that  depth  its  cost  will 
be  increased  about  in  the  ratio  of  the  increased  depth.  In- 
asmuch as  four  inches  will  afford  ample  strength  and  weight 
to  resist  the  wear  of  the  traffic  to  which  this  description  of 
pavement  is  suited,  there  appears  to  be  no  reason  for  mate- 
rially increasing  the  width  beyond  that  named  unless  it  be  to 
meet  exceptional  cases.  In  the  future,  should  it  appear 
that  brick  are  so  perfected  as  to  be  able  to  carry  the  ex- 
tremely heavy  traffic  concentrated  upon  business  thorough- 
fares, where  granite  block  pavements  are  now  thought  to  be 
most  suitable,  a  greater  width  may  be  found  desirable.  The 
length  of  the  brick  or  block  should  be  about  twice  its  width; 


BRICK  FOR  STREET  PAVEMENTS.  85 

its  thickness  should  not  exceed  its  width  and  may  be  made 
equal  to  it,  providing  such  a  block  can  be  properly  burned. 
The  writer  does  not  say  that  manufacturers  can  not  properly 
dry  and  burn  a  brick  three  or  four  inches  in  thickness,  but 
he  does  say  that  they  do  not  do  it.  The  conditions  and  the 
experience  all  indicate  failure  when  massive  pieces  of  clay 
are  sought  to  be  burned  into  bricks  or  blocks  suitable  for 
street  paving.  The  nearest  approach  to  success,  has  been  at- 
tained by  making  the  block  hollow  on  the  lower  side  in  or- 
der to  facilitate  burning.  For  the  solid  block  a  thickness  of 
two  inches,  or  at  most,  two  and  one-half  inches,  is  as  great 
as  should  be  attempted.  Even  where  the  clays  can  be  melted 
or  "  vitrified "  readily,  there  is  great  risk  incurred  in  at- 
tempting to  increase  the  thickness,  for  such  clays  usually 
contract  greatly,  and  the  outer  surface  is  almost  certain  to 
be  fixed  or  seared  by  the  intense  heat  before  the  inner  por- 
tions shall  have  been  so  acted  upon  as  to  produce  the  re- 
quired vitrification.  As  a  consequence  they  come  from  the 
kiln  either  insufficiently  burned,  checked  with  "  fire  cracks," 
either  internal  or  external ;  or,  like  an  ill-shaped  casting,  so 
affected  by  internal  strains  as  to  have  no  certain  amount  of 
strength.  Better  results  are,  therefore,  likely  to  be  secured 
by  adopting  about  the  building  brick  dimensions  than  by  at- 
tempting to  manufacture  blocks  of  a  larger  size.  Unfor- 
tunately those  dimensions  have  never  been  determined  with 
much  accuracy  in  this  country,  but  they  should  be,  and  then 
let  manufacturers  vary  the  dimensions  of  their  molds  as  the 
contractility  of  the  clays  vary,  so  that  bricks  of  equal  hard- 
ness shall  be  of  like  dimensions. 

It  may  be  argued  that  the  increased  number  ot  joints  in 
a  given  area,  caused  by  the  thinner  block,  constitute  an  ele- 
ment of  weakness  and  should,  therefore,  be  avoided.  The 
defect  is  more  imaginary  than  real,  since  the  proposition  can 


8G  BRICK    FOR    STREET    PAVEMENTS. 

not  be  true  if  made  general.  The  perfect  pavement  would 
become  one  without  joints,  which  is  impracticable  unless 
made  of  a  substance  sufficiently  yielding  or  elastic  to  afford 
secure  footing  for  animals,  which  practically  makes  it  a 
surface  of  innumerable  joints.  An  advantage  claimed  for 
brick  pavements  is  said  to  be  the  fact  that  they  can  be  so 
closely  laid,  and  the  joints  so  completely  filled,  that,  while 
they  furnish  secure  footing  for  animals,  they  are  so  smooth 
as  to  be  quiet,  and  so  impervious  as  to  be  cleanly.  If  this 
be  true,  the  additional  number  of  joints  is  not  objection- 
able. They  are  not  an  element  of  weakness,  since  the  load 
must  in  any  case  be  carried  by  the  foundation,  and  the  up- 
per and  lower  surfaces  being  equal,  the  weight  transmitted 
by  the  brick  will  be  as  its  area.  Should  the  surface  of  the 
foundation  be  uneven,  the  smaller  block  is  less  liable  to  be 
tilted  by  an  unequal  pressure  than  the  larger  one.  Within 
reasonable  limits,  therefore,  the  safe  course  to  pursue  would 
undoubtedly  lie  in  the  direction  of  the  thinner  blocks ;  or, 
in  other  words," to  adopt  a  standard  size  for  paving  blocks 
corresponding  with  building  brick  dimensions. 


COUNTRY  KOADS. 


INTRODUCTORY. 

In  a  paper  which  the  writer  read  before  the  club  some 
months  since,  the  words  "  Country  Roads  "  appeared  in  the 
title,  but  the  feature  of  the  subject  then  treated  contained 
little  of  practical  application,  under  existing  conditions,  to 
the  improvement  of  highways.  That  paper  was  a  plea  for  the 
betterment  of  surrounding  conditions.  This  is  written  (by 
request)  in  the  hope  that  it  may  contain  information  applica- 
ble, under  existing  regulations,  to  the  improvement  of  our 
common  roads.  No  attempt  will  be  made  to  treat  the  subject 
either  systematically  or  exhaustively,  as  the  field  is  too  broad 
to  be  so  traversed  in  the  limits  of  one  paper;  but  certain 
features  will  be  presented  which  we,  as  practicing  civil  engin- 
eers, should  endeavor  to  keep  before  the  minds  of  those  who 
expend  moneys  for  road  improvements.  Our  efforts  in  this 
direction  are  from  patriotic  motives  only,  for,  as  engineers,  we 
neither  ask  for,  nor  expect  any  part  in  the  direction  of  such 
work  until  after  the  conditions  which  now  environ  it  shall 
have  been  radically  changed. 

There  is  continued  and  growing  public  interest  in  the 
subject.  Quite  recently  we  have  been  favored  with  the  "Re- 
port of  the  Ohio  Road  Commission,"  which  was  appointed 
by  our  governor  to  investigate  and  report  upon  the  matter. 
Some  people  have  regarded  the  labors  of  that  commission  as 
disappointing,  but  their  conclusion  is,  at  least,  a  relief  to  us 

(87) 


88  COUNTRY   ROADS. 

for  the  present.  When  persons  who  are  unaccustomed  to 
wandering  in  the  realms  of  applied  science,  get  lost  upon 
such  expeditions  the  result  should  not  be  surprising. 

There  is  a  constant  tendency  to  exaggerate  the  subject, 
and  make  it  appear  necessary  to  expend  millions  of  dollars 
for  the  building  of  costly  highways  in  all  localities,  regard- 
less of  the  necessity  or  use  for  such  things.  It  will  be  the 
aim  in  this  paper  to  attract  attention  to  methods  by  which 
existing  evils  in  our  common  roads  may  be  greatly  alle- 
viated without  adding  to  the  burden  of  the  tax-payer,  and 
to  a  betterment  of  the  results  that  are  attainable  where 
larger  expenditures  are  being  made  for  so-called  road  im- 
provements. 

LOCATION. 

By  far  the  larger  portion  of  existing  country  roads  have 
been  located  along  section  lines  or  farm  boundaries,  without 
reference  to  the  topography  of  the  country  through  which 
they  pass.  In  many  instances  these  locations  are  as  they 
should  be,  while  in  others  their  improvement  and  mainte- 
nance upon  present  lines  are  wasteful  processes.  When  they 
are  revie*wed  or  relocated,  or  when  a  new  line  is  to  be  opened, 
the  position  of  the  road  is  dictated  by  three  citizens  acting 
in  the  capacity  of  viewers.  The  surveyor  or  engineer,  which- 
ever he  may  be  called,  runs  the  line  where  he  is  told  by  them  to 
place  it.  To  many  people  it  would  seem  that  this  regulation 
should  be  changed,  but  a  hasty  conclusion  in  the  matter  might 
make  it  worse,  because,  as  between  the  intelligent  farmer  and 
the  country  surveyor  who  ordinarily  officiates  on  such  occa-' 
sions,  the  former  is  generally  far  the  better  road  builder  of  the 
two.  If  the  power  to  determine  the  location  be  placed  in  the 
hands  of  the  surveyor,  the  regulation  will  be  bettered  only 
when  he  is  better  qualified  to  exercise  that  power  than  are 
the  viewers.  Such  knowledge  is  not  conveyed  by  statutory 


COUNTRY   ROADS.  89 

enactments,  and  these  can  be  of  little  avail,  except  in  the  way 
of  preventing  incompetent  persons  from  doing  such.  work. 
As  a  preliminary  step,  it  would  appear  to  be  proper  to  so 
amend  the  law  as  to  require  the  assent  of  the  surveyor,  or 
allow  him  to  submit  a  minority  report,  and  thus  put  at  least 
as  much  responsibility  upon  him  as  a  viewer  has.  In  many 
oases  this  would  be  beneficial,  and  where  the  work  should  be 
done  by  an  engineer  having  a  knowledge  of  topography,  it 
would  enable  him  to  prevent  waste.  In  the  opening  of  new 
lines  likely  to  become  thoroughfares,  the  application  of 
fessional  knowledge  would  be  a  desirable  innovatio 

DIRT  ROADS. 

Assuming  the  location  as  made,  the  next  step  i 
pare  the  soil  to  sustain  the  travel  to  be  brought  upon  it. 
far  the  greater  part  of  the  mileage  of  our  country  high- 
ways is  composed  of  dirt  roads.  This  condition  must  so  re- 
main for  many  years  to  come.  If  they  are  properly  treated, 
they  will  be  changed  to  other  forms,  only  when  they  are  re- 
quired to  carry  heavy  and  continuous  traffic.  The  larger 
part  of  these  highways  can  be  made  and  maintained  as  good 
drives  without  great  expense,  and  without  covering  them  to 
any  considerable  depth  with  gravel,  broken  stone,  or  other 
paving. 

Natural  forces  are  always  at  work  disintegrating  all 
substances  on  the  surface  of  the  earth,  and  turning  them 
into  soil.  On  those  portions  to  be  used  as  roads,  our  efforts 
should  be  to  neutralize,  as  far  as  is  practicable,  the  effect  of 
these  natural  forces,  and  make  those  portions  sterile  and  un- 
changeable. If  then  the  surface  be  deprived  of  the  lighter 
vegetable  mold,  be  made  compact  and  smooth,  so  that  it 
will  carry  the  traffic  without  being  displaced  by  it,  and  so 
that  water  falling  upon  it  shall  neither  remain  thereon  nor 


90  COUNTRY  ROADS. 

penetrate  into  it,  we  shall  have  a  good  dirt  road,  which,  so 
long  as  these  conditions  obtain,  is  literally  and  truly  the  best 
road  on  earth.  But  how  shall  we  bring  about  and  maintain 
these  conditions  ?  The  attacking  forces  are  wind,  water,  and 
frost.  Excepting  in  arid  regions,  the  arch  enemy  is  water, 
frost  not  being  detrimental,  except  when  aided  by  moisture. 
Thorough  drainage  therefore  is  the  first  requisite. 

Inasmuch  as  the  dirt  road  is  neither  suitable  for,  nor  capa- 
ble of,  carrying  heavy  and  continuous  traffic,  its  width  should 
not  be  great.  From  10  to  18  feet  will  be  sufficient  width  for 
the  roadway  proper.  The  correct  treatment  for  each  caser 
can  only  be  determined  by  the  skillful  practitioner.  In  some 
localities  subsoil  drainage  is  wholly  useless,  while,  generally, 
no  durable  roadway  can  be  made  without  it. 

Assuming  that  we  have  plows,  harrows,  scrapers,  teams,, 
and  hand  tools  common  in  the  country,  and  in  addition 
thereto  an  ordinary  road  grader  and  a  five  ton  horse-roller, 
let  us  see  what  it  will  cost  to  make  a  mile  of  fairly  good  dirt 
road  in  what  would  be  termed  a  level  swampy  country.  The 
subsoil  is  a  tenacious  clay.  The  top  4  to  6  inches  being  a. 
light  vegetable  mold,  the  ideal  position  for  an  impassable 
road  in  wet  weather.  We  have  a  profile  of  our  line  and  find 
two  places  in  the  mile  where  we  can  discharge  water,  and 
at  those  points  we  lay  24  inch  drain-pipes  across  the  road- 
way. We  do  not  find  it  advisable  to  make  any  material 
changes  in  the  grade  of  the  roadway,  but  decide  to  make  a, 
space  16  J  feet  wide  near  the  center,  so  that  it  can  be  traveled 
upon.  We  have  no  rock,  but  at  an  average  haul  of  two 
miles,  we  can  get  a  coarse  sand  or  fine  gravel  from  the  bars 
in  a  small  stream  at  a  cost  of  10  cents  per  wagon  load  plus, 
the  hauling.  Our  profile  shows  that  we  can  place  tile  drains 
3  feet  deep  at  the  summits,  give  them  a  fall  of  2  feet  per 
1,000  feet  toward  the  outlets  and  that  their  average  depth 


COUNTRY    ROADS.  91 

will  be  4  feet.  Of  course  the  tile  drains  are  larger  near  the 
outlets  and  smaller  near  the  summits,  but  we  find  the  aver- 
age size  5  inches  and  the  average  cost  5  cents  per  foot.  We 
allow  $3.00  per  day  for  teams,  $1.25  per  day  for  labor.  We 
adopt  the  following  cross-section  for  our  work  and  proceed 
with  its  construction  in  this  manner : 

SECTION  OF  DIRT  ROAD. 
(Scale — One  inch  equals  eight  feet.) 


First  with  light  plows  to  loosen  it,  scrapers  to  handle  it,, 
arid  our  grader  to  give  us  a  smooth  surface,  we  remove  the 
vegetable  mold  for  a  width  of  24  feet.  Then  we  pass  over 
the  surface  with  our  roller  to  see  that  its  sustaining  power  is 
uniform.  Where  it  is  not,  we  make  it  so,  cutting  from  the 
high  and  filling  in  the  low  places,  and  rerolling  until  we  ob- 
tain an  equable  foundation.  Next,  we  lay  out  and  dig  our 
trenches  and  place  the  tile  drains.  We  finish  the  trenches 
and  lay  the  tile  very  carefully,  for  we  must  have  close  joints 
and  uniform  gradients.  We  use  all  the  clay  obtained  from 
these  trenches  on  our  roadway,  and  find  that  by  digging 
them  18  inches  wide  at  the  top  and  12  inches  at  the  bottom 
we  can  cover  it  8  inches  deep  in  the  center  and  4  inches- 
deep  at  the  sides.  We  spread  it  evenly  to  this  form,  harrow 
it  to  break  any  lumps  and  make  it  smooth,  and  while  it  ia 
still  moist  from  the  trench  and  loose  from  the  harrowing^ 
we  spread  very  coarse  sand  or  fine  gravel  over  it  to  the 
depth  of  one  inch,  and  roll  it  until  the  surface  is  perfectly 


92  COUNTRY    ROADS. 

smooth  and  hard.  We  fill  over  our  tile  drains  in  the  bot- 
toms of  our  trenches  to  the  depth  of  one  foot  with  coarse 
sand,  and  the  residue  of  the  back  filling  is  done  from  the 
waste  banks  of  loam,  except  that  at  intervals  of  about  50 
feet,  we  fill  one  foot  in  length  of  the  trench  with  sand  to  the 
top.  We  compact  this  back  filling  by  driving  our  wagon 
wheels  on  it,  smooth  out  the  gutters  to  a  depth  of  about  one 
foot,  spread  some  loam  on  them,  and  sow  them  with  grass 
seed.  We  must  do  all  of  this  work  like  we  do  our  farm 
work — when  the  soil  is  in  suitable  condition.  Now  let  us 
see  what  a  mile  of  it  will  cost : 

Removing  the  loam,  6c.  per  lineal  foot $316  80 

Two  tile  drains,  5c.  each^lOc.  per  lineal  foot 528  00 

Trenching,  laying,  and  back  filling,  7c.  each=14c...  739  20 

660  cubic  yards  sand  or  gravel,  at  50c.  per  yard 330  00 

Grading  up  and  rolling.. 85  00 

80  feet  of  24"  drain  pipe  in  place,  at  $1.50  120  00 

Seeding  gutters , 10  00 


Total $2,129  00 

Or,  in  round  numbers,  $2,100.00  per  mile  will  transform 
the  very  worst  of  our  country  roads  into  highways  much 
better  suited  to  the  limited  traffic  which  they  have  to  carry 
than  they  would  be  were  they  changed  to  undrained  gravel 
or  broken  stone  roads. 

The  treatment  described  is  not  suitable  for  universal  ap- 
plication, but  for  the  location  outlined.  Only  those  who 
from  actual  experience  know  the  results  that  will  follow,  will 
have  any  faith  in  such  work;  but  we  do  know,  and  we 
should  induce  others  to  try  it  and  be  convinced. 

In  undulating  countries,  enough  grading  should  be  done 
to  avoid  the  necessity  of  traveling  up  and  down  a  succession 


COUNTRY    ROADS.  93 

of  steep  hills,  and  to  form  the  roadway  properly,  but  the 
construction  of  long  embankments  or  deep  cuts  in  order  to 
comply  with  some  theoretical  gradient  is  very  generally  a 
mere  waste  of  money.  The  direction  of  currents  of  water 
upon,  within,  and  from  the  soil  must  be  studied,  and  drains 
placed  to  intercept  them  and  prevent  the  saturation  of  the 
soil  which  carries  the  traffic,  and  when  it  has  been  compacted 
in  the  proper  form  it  will  permanently  remain  a  good  road, 
unless  the  traffic  is  beyond  its  endurance,  and  that  would  not 
be  the  case  upon  ten  per  cent  of  the  country  roads.  When 
that  should  occur,  nothing  that  had  previously  been  done 
would  have  been  lost,  for  all  of  that  work  is  necessary  to 
prepare  a  foundation,  and  it  would  only  be  required  to 
place  upon  it  a  wearing  surface  having  a  higher  power  of 
resistance. 

In  level  districts,  the  roadway  should  generally  be  a  foot 
or  more  above  the  adjacent  lands,  which  will  naturally  result 
from  constructing  the  side  drains.  In  no  case  should  there 
be  a  sharp  crowning  of  the  center,  as  that  always  results  in 
concentrating  the  travel  upon  the  highest  part,  inevitably 
producing  ruts.  Whatever  width  may  be  given  the  road- 
way, every  portion  should  be  equally  good,  that  the  wear 
upon  it  shall  be  distributed. 

Loamy  soils  and  clays  can  be  made  quite  firm  by  com- 
pacting in  thin  layers,  and  so  draining  them  as  to  hold  the 
water  line  from  two  to  four  feet  below  the  surface,  but  they 
absorb  water  with  great  avidity,  and  will  become  so  satur- 
ated as  to  lose  their  sustaining  powers  for  at  least  a  foot 
above  the  level  of  standing  or  running  water.  The  drains 
should,  therefore,  be  from  three  to  five  feet  below  the  surface 
of  the  roadway,  wherever  practicable.  If  subsoil  drains  are 
required  between  the  side  ditches,  they  should  be  made  of 


94  COUNTRY   ROADS. 

•coarse  gravel  or  rock,  wherever  such  material  is  obtainable, 
rather  than  of  tile. 

Open  side  ditches  of  the  requsite  depth  are  generally 
objectionable,  but  where  the  subsoil  is  porous,  like  deposits 
of  sand  or  gravel  covered  by  loamy  soil  a  few  feet  in  thick- 
ness, a  side  ditch  of  moderate  depth  can  be  made  to  answer 
every  purpose  by  sinking  shafts  in  it,  at  frequent  intervals, 
to  the  underlying  gravel  and  filling  them  with  gravel  or 
•coarse  sand.  These  act  as  inlets  to  the  pervious  stratum, 
and  conduct  the  surface  water  quickly  to  it.  Wherever 
drains  are  laid,  an  accurate  map  should  be  made  of  their  lo- 
cations, depths,  and  connections,  and  the  record  be  accessi- 
ble to  the  parties  having  in  charge  the  maintenance  of  the 
works. 

Where  the  soil  is  shallow,  and  rock  in  continuous  ledges 
lies  near  the  surface,  deep  ditches  or  drains  may  be  utterly 
impracticable,  but  shallow  trenches  skillfully  located  may 
prevent  the  water  from  reaching  the  roadway,  providing  the 
^exact  dip  and  trend  of  the  rock  be  known.  Piling  material 
on  rock  surfaces  where  the  water  is  pocketed,  will  never  re- 
sult in  good,  while  the  best  of  drives  can  be  cheaply  con- 
structed in  such  localities  by  properly  draining  them,  and 
this  can  very  generally  be  done  at  little  expense. 

Occasionally  roads  must  be  constructed  across  marshy 
tracts  where  drainage,  at  the  time,  is  impracticable.  In  tim- 
bered countries  this  affords  "  the  corduroy  road,"  which  is 
merely  a  method  of  distributing  the  weight  over  a  sufficient 
area  to  bear  the  load.  A  mattress  of  poles  and  brush  cov- 
ered with  earth  is  generally  the  cheapest  and  best  construc- 
tion in  such  exceptional  cases.  Drainage  can  usually  be  had 
when  the  proper  search  is  made  and  wider  areas  are  em- 
braced in  the  examination. 

Combining  materials  found  in  close  proximity  to  each 


COUNTRY   ROADS.  95 

other  frequently  adds  greatly  to  the  stability  of  the  soil.  A 
fine  sand  may  be  merely  loosened  by  the  travel  and  carried 
away  by  the  winds  and  rains,  while  if  covered,  even  lightly, 
by  a  coarse  sand  or  fine  gravel,  it  will  remain  in  place  and 
make  an  excellent  road.  A  plastic  clay  may  retain  the 
moisture  of  each  passing  shower  to  such  an  extent  as  to  be 
an  unsuitable  road,  while  if  covered  with  a  thin  layer  of 
sand  or  even  sandy  loam,  its  surface  will  become  smooth  and 
shed  water  like  a  tin  roof.  Where  no  sand  can  conveniently 
be  had,  a  coating  of  burned  clay  a  few  inches  in  depth  will 
make  an  excellent  road  for  moderate  traffic  at  small  cost. 
In  all  clay  and  loamy  soils,  the  drainage  of  the  surface  and 
subsoil  is  the  first  essential. 

Roads  located  along  hillsides  will  require  but  a  single 
ditch  adjacent  to  the  hill,  which  should  be  from  one  to  two 
feet  lower  than  the  surface  of  the  traveled  way,  and  at  fre- 
quent intervals  outlets  should  be  provided  for  the  water  to 
pass  beneath  the  road  to  the  adjacent  lowland.  In  locali- 
ties where  rock  is  not  too  expensive,  the  best  conduit  is  the 
old-fashioned  stone  box  drain  with  paved  bottom  and  dry 
wall  sides.  The  rock  cover  should  have  at  least  two  feet  of 
earth  upon  it. 

In  the  deep  black  muck  of  the  prairies,  especially  where 
the  descent  to  the  water-courses  is  very  slight,  the  ditches  or 
side  drains  will  need  especial  care,  but  even  these  soils  will 
sustain  a  considerable  traffic  if  the  water  level  can  be  kept 
three  or  four  feet  lower  than  the  traveled  surface  of  the 
roadway. 

The  principle  involved  in  combining  soils  for  a  wearing 
surface,  is  the  same  that  applies  to  the  successful  formation  of 
a  puddle  wall  or  the  making  of  concrete.  Clay  being  com- 
posed of  more  minute  particles  than  any  other  substance 
composing  the  soil,  becomes  the  filler  or  mastic,  which,  com- 


96  COUNTRY   ROADS. 

bined  with  the  coarser  fragments  of  sand  or  rock,  is  by  them 
held  in  position  and  prevented  from  forming  a  solution  with 
water.  Vegetable  mold  being  lighter  than  any  other  com- 
ponent of  the  soil,  having  greater  affinity  for  moisture,  and 
expanding  so  greatly  when  frozen,  has  not  been  successfully 
treated  as  an  element  in  road  construction.  On  the  contrary, 
its  presence  in  any  considerable  quantity  is  sure  to  render 
the  soil  so  weak  as  to  require  protection.  If  well  drained, 
the  light,  loamy  soils  can  be  made  to  sustain  a  moderate 
traffic  by  a  light  covering  of  cinder,  gravel,  shells,  or  burned 
clay. 

The  repairing  of  dirt  roads  involves  only  the  work  inci- 
dent to  keeping  the  drains  and  ditches  open,  and  the  road 
surface  smooth,  so  as  to  prevent  the  formation  of  ruts  or  de- 
pressions that  will  retain  water.  The  broad  tire,  especially 
where  the  front  axle  of  the  four-wheeled  vehicle  is  shorter 
than  the  rear  one,  is  the  best  instrument  yet  devised  for  the 
preservation  of  road  surfaces. 

Where  there  is  a  considerable  descent  in  the  side  ditches, 
or  the  accumulation  of  water  in  them  is  great,  means  should 
be  taken  to  prevent  excessive  washing.  Placing  obstructions 
across  the  ditch,  so  as  to  divide  the  descent  into  a  series  of 
low  cascades,  is  frequently  the  most  simple  and  effective 
means  of  preventing  the  formation  of  deep  gullies.  The  se- 
cret of  success  in  disposing  of  surface  water  lies  in  conduct- 
ing it  to  natural  channels  in  small  quantities,  and  thus  avoid- 
ing the  handling  of  great  accumulations. 

The  traffic  which  can  be  economically  carried  by  the  dirt 
road  will  vary  greatly  with  different  soils,  but  the  treatment 
above  outlined  is  all  that  is  required  upon  more  than  two- 
thirds  of  the  present  mileage  of  public  roads.  As  they  ap- 
proach commercial  centers,  or  connect  towns,  thus  assuming 
the  nature  of  thoroughfares,  it  will  be  necessary  to  supply  a. 


COUNTRY    ROADS.  97 

wearing  surface  of  greater  resisting  power,  and  next  in  rank 

will  come 

THE  GRAVEL  ROAD, 

In  almost  all  parts  of  the  country  there  are  deposits  of 
gravel  available  for  road  construction,  and  it  is  the  most 
economical  material  for  road  making,  when  it  is  found 
necessary  to  assist  the  bearing  power  of  the  soil,  and  the 
amount  of  traffic  is  not  too  great.  Generally  its  applica- 
tion is  merely  that  of  a  "  dryer,"  but  frequently  the  pebbles, 
sand  and  clay  become  united,  forming  a  concrete  that  makes 
a  serviceable  road.  The  calcareous,  or  limestone  gravels, 
are  very  popular  in  road  making,  because  of  their  tendency 
to  become  consolidated,  or  "pack"  under  traffic.  They 
are,  however,  more  dusty  in  dry  weather,  more  muddy  in 
wet  weather,  and  as  a  consequence,  less  durable  and  pleas- 
ant than  the  silicious  gravels.  Where  no  lime  or  clay  is 
present,  it  is  necessary  to  have  the  proper  combination  of 
sizes,  or  there  will  be  a  lack  of  "•  bond."  Frequently  clay  or 
loam  is  added  to  induce  consolidation,  but  this  practice  is 
generally  wrong.  Sands  of  various  degrees  of  fineness  are 
gener  ally  available,  which,  in  combination  with  water  and 
pressure,  will  form  a  bond  that  will  not  be  disturbed,  either 
by  excessive  moisture,  or  frost,  as  will  the  bond  formed  by 
the  use  of  clay  or  loam. 

The  proper  formation  of  the  grade  preparatory  to  placing 
the  gravel  upon  it,  has  been  sufficiently  described  in  that 
which  has  been  said  about  the  dirt  road.  It  is  just  as  essen- 
tial that  the  soil  should  be  drained,  given  the  proper  form 
and  compacted  to  receive  th,e  gravel,  as  that  it  should  be,  to 
carry  the  traffic  itself.  The  rolling  of  a  coating  of  gravel, 
about  an  inch  in  depth,  into  the  subgrade,  is  good  practice, 
but  the  use  of  the  roller  on  heavy  layers  of  gravel  is  of  little 
practical  utility.  A  little  labor  and  water  expended  in  keep- 


98  COUNTRY  ROADS. 

ing  the  surface  smooth  while  the  road- way  is  being  com- 
pacted by  the  traffiic,  is  of  greater  benefit. 

As  ordinarily  applied,  gravel  is  rather  wastefully  used, 
mainly  from  lack  of  care  in  forming  the  subgrade,  and  fre- 
quently from  excessive  use  in  repairs.  A  thickness  of  six  or 
seven  inches  at  the  sides,  and  from  eight  to  ten  inches  in  the 
center  of  the  roadway  will  be  found  sufficient  where  the 
ground  has  been  properly  prepared,  to  make  very  good  roads 
where  the  traffic  is  not  too  heavy.  On  account  of  its  insta- 
bility, the  gravel  road  should  be  given  a  little  higher  crown 
in  the  center,  than  either  the  earth  or  macadam  road,  but 
the  practice  is  greatly  in  excess  of  the  requirement  in  this 
particular.  On  grades  of  three  per  cent  or  less,  a  rise  toward 
the  center  of  an  inch  in  four  feet  will  be  found  sufficient. 
On  steeper  gradients,  the  crown  should  be  slightly  increased. 
The  gravel  roadway  is  not  suitable  for  long  slopes  or  steep 
gradients. 

The  practice  of  constructing  a  berm  or  earth  shoulder 
at  the  side  to  hold  the  gravel  in  place  is  correct,  providing 
the  gravel  be  extended  through  this  berm  to  the  side  ditches 
at  frequent  intervals  in  order  to  afford  proper  drainage.  Such 
openings  may  be  covered  with  earth,  where  grass  is  to  be 
grown  or  to  prevent  wash,  but  they  should  in  no  case  be  omit- 
ted. As  they  are  not  expensive,  it  is  better  to  provide  too  many 
than  too  few.  Where  sand  is  plentiful,  a  continuous  layer  two 
inches  in  depth  beneath  the  earth  shoulder,  is  good  practice. 
"Where  it  is  more  economical,  a  space  one  foot  wide  by  six 
inches  deep,  sunk  three  inches  into  the  subgrade,  at  inter- 
vals of  50  feet  on  each  side,  will  usually  drain  the  roadway. 
The  gravel  road,  while  new,  will  require  almost  constant  at- 
tention, or  it  will  not  remain  in  proper  form  under  any  con- 
siderable traffic.  Its  cost  will  be  that  of  the  gravel  coating 
added  to  that  of  preparing  the  dirt  road  as  heretofore  de- 


COUNTRY    ROADS.  99 

scribed.  This  coating  will  cost  from  $800  to  $1,500  per  mile, 
varying  with  the  width  of  roadway  adopted,  the  value  of  the 
gravel  and  the  distance  it  must  be  hauled.  It  is  true,  that 
two  or  three  times  the  depth  of  gravel  above  mentioned 
piled  along  the  center  of  a  mud  road  without  any  particular 
attentiou  to  drainage  will  generally  make  a  single  track 
along  it  passable  at  most  seasons  of  the  year,  but  gravel 
roads  of  that  description  are  not  desirable  improvements, 
and  even  if  they  are  better  than  no  change  at  all,  they  should 
be  discouraged  because  they  are  wasteful. 

MACADAM  OR  BROKEN  STONE  ROADWAYS. 

The  preparation  of  the  roadway  for  the  reception  of  the 
broken  stone,  is  the  essential  feature  necessary  to  secure  a 
good  road.  An  inferior,  shaly  limestone,  but  a  few  inches 
in  depth,  on  a  well  drained,  properly  prepared  grade,  will 
make  a  better  road  than  the  best  whinstone  or  crushed  gran- 
ite of  three  times  the  depth,  put  on  an  uneven,  undrained 
roadway.  It  is  obvious  that  the  soil  must  carry  the  weight, 
and  that  the  covering  of  metal  placed  upon  it  can  only 
serve  two  purposes,  which  are,  first,  to  distribute  the  pres- 
sure ;  and  second,  to  resist  the  abrading  effect  of  the  traffic ; 
therefore,  the  preparation  of  a  proper  foundation  is  just  as 
essential  in  road  building  as  it  is  in  any  other  engineering 
construction.  This  feature  is,  however,  very  commonly 
neglected,  and  probably  no  better  way  of  illustrating  the 
matter  can  be  chosen  than  to  first  describe  how  such  work  is 
done,  and  follow  by  telling  how  it  might  be  done. 

Let  it  be  assumed  that  the  people  of  a  certain  locality 
desire  the  opening  of  a  new  road  a  few  miles  in  length,  the  route 
being  partly  in  a  rolling  country  of  limestone  hills,  partly 
decending  across  drift  deposits  of  clay  and  gravel,  and  partly 
in  alluvial  bottom  lands.  The  usual  forms  of  law  in  such 


100  COUNTRY    ROADS. 

cases  have  been  complied  with,  the  county  engineer,  in  obe- 
dience to  the  order  of  the  commissioners,  has  prepared  a 
profile  and  an  estimate  that  fits  the  appropriation  with 
specifications  that  fit  any  thing  of  the  kind,  the  work  is 
advertised,  bids  are  received,  and  a  contract  awarded  for 
building  the  road  and  the  work  begins.  The  profile  shows  a 
succession  of  cuts  and  fills  to  a  grade  which  the  commission- 
ers wisely  reserve  the  right  to  change  as  they  may  deem 
proper,  or  the  state  of  the  available  fund  may  require.  Sundry 
culverts  or  drain  pipes  are  provided  for,  where  the  line  is 
crossed  by  water-courses  or  ravines,  but  no  other  drainage  is 
contemplated  except  that  from  the  special  fund.  An  embank- 
ment is  placed  upon  the  side  of  a  limestone  hill,  but  it  refuses  to 
remain  in  position  as  per  plan,  and  sullenly  moves  down  the 
slope  carrying  the  proposed  roadway  with  it  and  involving  a 
few  buildings  and  other  improvements  in  disaster.  A  cut  is  made 
through  a  drift  deposit,  and  a  few  acres  of  the  adjacent  ground 
on  the  upper  side  of  the  road  slowly  begin  to  gravitate  into  the 
cavity  thus  formed,  carrying  their  burdens  with  them.  These 
movements  are  sought  to  be  checked  by  pile-driving,  and  the 
building  of  retaining  walls.  Injured  property  owners  file 
claims  for  damages,  the  fund  is  exhausted,  the  contractor 
blamed,  but  no  road  is  completed.  An  additional  appropria- 
tion is  had  to  save  the  money  already  expended.  No  part  of 
the  road  has  been  completed,  but  all  parts  have  been  com- 
menced. The  former  and  the  latter  rains,  aided  by  the 
teaming  incident  to  the  grading,  has  rendered  it  necessary  to 
cover  the  graded  road-bed  with  some  thing,  and  as  fast  as  it 
can  be  brought  to  about  the  elevations  which  the  "  engineer  " 
designates,  the  contractor  hauls  upon  it  the  shaly  rock  from 
the  limestone  bluffs,  dumping  it  in  the  mud  to  about  the 
thickness  specified  for  the  bottom  course  of  metal,  and 
breaking  the  upper  portion  so  as  at  least  to  make  it  passable 


COUNTRY  ROADS.  101 

for  his  own  teams.  On  the  "foundation  "  thus  prepared  he 
hauls  broken  stone  of  similar  quality  to  the  specified  width 
and  depth,  covers  the  whole  with  gravel,  cleans  the  mud 
from  the  side  ditches,  which  he  carefully  banks  against  the 
stone  to  form  the  required  berm.  On  the  embankments  he 
forms  the  berm  by  robbing  the  slopes,  and  when  all  is  done 
securely,  fences  up  his  work  until  the  commissioners  inspect 
and  accept  it.  This  being  done  the  road  is  opened  to  a  de- 
lighted public.  It  is  true  that  sundry  damage  claims  are 
still  in  court,  that  the  contractor  has  filed  large  claims  for 
delays  and  extra  work,  that  the  slips  are  still  moving,  the 
road  very  muddy  and  almost  impassable  in  places,  but  there 
is  no  money  for  repairs,  the  thoroughfare  is  opened  and  the 
county  must  now  keep  it  open  cost  what  it  may. 

The  same  line  of  roadway  might  be  opened  in  a  differ- 
ent manner.  Instead  of  running  lines  in  impracticable 
places,  the  location  might  be  made  by  a  real  engineer,  one 
who  observes  the  effect  of  natural  causes  and  provides  for 
the  resultants  of  natural  forces.  He  knows  that  there  are 
currents  of  moisture  passing  beneath  and  through  the  soil  as 
well  as  those  visible  upon  its  surface,  and  that  in  road  build- 
ing it  is  as  essential  to  provide  for  one  as  for  the  other.  In 
the  limestone  hills,  he  knows  that  every  layer  of  stone  car- 
ries its  film  of  moisture  with  the  dip  to  its  margin,  whether 
that  be  an  exposed  edge  or  one  covered  with  soil,  and  hence, 
that  any  change  in  the  condition  or  duty  of  the  soil  must  be 
coupled  with  a  provision  for  the  disposal  of  the  soil  water,  or 
that  disaster  will  as  certainly  follow  as  it  would  were  he  to 
erect  xa  structure  of  iron  or  steel  exposed  to  changes  of  tem- 
perature and  make  no  provision  for  the  changes  in  length 
due  to  heat  or  cold.  His  survey  will,  therefore,  locate  the 
position,  dip,  and  strike  of  the  principal  rock  ledges,  the  di- 
rection and  approximate  flow  of  the  underground  currents 


102  COUNTRY   ROADS. 

that  will  be  likely  to  affect  his  work,  as  well  as  those  which 
visibly  pass  upon  the  surface  of  the  earth.  His  examination 
of  the  drift  deposits  will  be  made  with  great  care  respecting 
their  drainage  and  stability.  His  plans  will  show  and  speci- 
fications describe  the  work  that  is  to  be  done.  Landslides 
will  not  follow  in  the  wake  of  his  grading,  because  they  do 
not  come  by  chance,  and  his  plans  provide  for  natural  re- 
sults. Should  it  become  necessary  to  construct  an  embank- 
ment on  a  hillside,  the  foundation  for  such  a  till  will  be  pre- 
pared and  drained  with  as  much  care  as  it  would  be  for 
erecting  any  other  structure  of  equal  weight.  If  an  excava- 
tion is  necessary  through  a  supporting  mass  of  earth,  the 
cutting  will  be  done  and  equilibrium  restored  in  such  a  man- 
ner that  motion  will  not  be  imparted  to  material  which  is 
desired  to  remain  in  place. 

Both  soil  and  surface  waters  will  be  intercepted  and  led 
away  from  the  roadway,  so  that  its  condition  in  regard  to 
moisture  shall  be  as  nearly  as  practicable  constant,  or  at 
least  so  that  it  shall  in  no  case  become  saturated.  In  the 
limestone  hills,  the  ditches  may  be  shallow,  but  they  will 
be  so  placed  as  to  lead  away  the  surface  water  and  intercept 
the  ground  water,  and  it  will  always  be  borne  in  mind  that 
the  latter  function  is  the  more  important  of  the  two.  In  the 
clay  soil  and  drift,  the  side  drains  will  be  placed  from  two  to 
four  feet  below  the  soil  of  the  roadway,  and  the  trenches 
filled  with  sand  or  other  porous  material,  always  connecting 
them  through  the  berm  with  the  sand  covering  of  the  sub- 
grade.  . 

In  forming  the  subgrade,  he  will  see  that  it  is  smooth 
and  firm,  and  by  rolling  and  dressing  is  given  a  uniform  sus- 
taining power.  On  grades  of  three  per  cent  or  less,  it  will 
rise  from  the  berm  of  the  side  ditch  toward  the  center  or 
crown  of  the  street  with  a  slope  of  one  inch  in  five  feet ;  on 


COUNTRY   ROADS.  103 

steeper  gradients  it  may  rise  one  inch  in  four  feet,  but  it  will 
be  smooth,  firm,  and  all  alike.  He  will  cover  it  evenly  with 
a  layer  of  coarse  sand  or  fine  gravel  for  its  entire  width  to  a 
depth  of  not  less  than  two  nor  more  three  inches.  This 
sand  will  join  that  leading  to  and  enveloping  the  subsoil 
drains.  This  layer  of  sand  does  several  things.  It  inter- 
cepts and  leads  to  the  drains  the  moisture  that  exudes  from 
the  soil,  especially  on  grades  or  slopes,  preventing  it  from 
percolating  into  the  broken  stone.  It  prevents  the  frost 
from  forcing  the  loamy  clay  upward  into  the  stone  in  winter. 
It  forms  a  cushion  between  the  soil  and  the  stone,  accommo- 
dating itself  to  the  shape  of  the  rock  and  preventing  the 
clay  from  rising  into  and  through  the  stone  when  subjected 
to  the  pressure  of  traific. 

On  this  layer  of  sand  he  will  cause  to  be  spread  broken 
stone  unmingled  with  shale  or  clay  to  an  even  thickness  of 
five  inches.  The  office  of  this  layer  of  stone  is  to  distribute 
the  weight  of  traffic  upon  the  foundation.  It  is  not  essential 
that  it  should  be  of  very  refractory  or  expensive  material, 
but  it  must  not  be  such  as  will  be  disintegrated  by  frost  or 
rain,  and  its  crushing  strength  should  not  be  less  than  5,000 
pounds  per  square  inch.  The  fragments  should  be  cubical 
or  angular,  not  thin  and  flat,  and  should  not  exceed  three 
inches  in  any  dimension ;  if  the  rock  has  a  low  crushing 
strength,  four  inch  pieces  would  be  admissible.  It  should  be 
well  compacted  by  rolling.  The  rolling  should  be  commenced 
at  the  margins,  and  by  laps  of  one-third  or  less  of  the  length 
of  the  roller  progress  toward  and  finish  at  the  center.  It 
should  be  continued  until  the  gravel  begins  to  appear  near 
the  surface  of  the  stone.  The  earth  shoulders  should  be 
built  up  just  in  advance  of  the  spreading  of  this  bottom 
layer  of  stone.  They  should  be  placed  on  sand  or  be  pro- 
vided with  sand  drains,  as  described  in  Gravel  Roads. 


104  COUNTRY    ROADS. 

The  road  is  now  ready  for  the  wearing  surface.  If  it  is 
a  broad  avenue  thirty  feet  or  more  in  width,  which  is  to  carry 
a  burden  of  hundreds  of  vehicles  daily,  a  depth  of  six  inches 
of  stone  in  the  center  and  four  inches  at  the  sides  may  be 
used;  but  for  the  ordinary  country  road,  like  our  "free 
pikes,"  four  inches  in  the  center  and  three  at  the  sides  will 
be  found  quite  sufficient.  The  most  refractory  or  hardest 
rock  that  can  be  obtained  at  reasonable  cost  must  be  used. 
It  should  be  crushed,  screened, -and  used  in  three  sizes,  if  they 
can  readily  be  had.  Trap,  any  of  the  granitic  rocks  or  whin- 
stones,  and  most  of  the  metamorphic  rocks,  make  excellent 
road  surfaces.  Limestones  are  more  common,  and  when  only 
sound  crystalline  stone  is  used  they  are  quite  durable.  The 
first  layer  spread  on  the  street  as  above  described  should  be 
in  fragments  not  exceeding  two  and  a  half  inches  in  any  di- 
mension, and  it  should  be  raked  to  an  even  surface  about 
three  inches  thick,  being  a  little  thicker  at  the  center  than  at 
the  sides.  It  should  be  covered  with  spalls,  that  is,  fragments 
of  rock  varying  in  size  from  one-quarter  to  three-quarters  of 
an  inch,  in  quantity  just  sufficient  to  fill  the  voids  in  the  stone, 
which  will  be  from  thirty  to  fifty  per  cent  of  the  quantity  of 
the  larger  size  of  crushed  stone.  Fifty  per  cent  will  seldom 
be  too  much,  because  the  spalls  will  work  downward  in  the 
bottom  course  until  they  meet  the  sand.  They  should  be 
worked  into  the  stone  with  steel  brooms  over  every  portion 
of  the  surface  dry,  as  long  as  any  will  go  down,  then  drench 
the  layer  with  a  sprinkling  cart,  and  pass  the  roller  over  it 
once  or  twice,  but  do  not  roll  it  hard.  Now,  if  you  have 
rock  broken  to  one  and  one-half  inch  size,  put  on  a  layer  of 
it  about  two  inches  in  depth,  spread  and  broom  into  it  all 
the  spalls  it  will  take,  drench  it,  roll  it,  and  keep  on  sweep- 
ing in  spalls  and  rolling  until  the  surface  of  your  road  is  as 
hard  as,  and  resembles  a  mosaic  pavement.  You  may  leave 


COUNTRY   ROADS.  105 

a  light  surplus  of  spalls  on  top,  but  very  light ;  there  must 
be  nothing  loose  for  muddy  wheels  to  pick  up,  and  no  frag- 
ments of  stone  to  be  in  the  way.  With  banks  all  smooth, 
drains  and  ditches  all  open,  your  road  is  ready  for  use.  The 
contractor  can  now  receive  his  final  estimate,  but  an  agreed 
amount  or  percentage  should  be  retained;  for  his  liability 
should  not  cease  for  at  least  one  year  after  the  roadway  shall 
have  been  opened  to  public  use.  The  contract  providing 
that  during  that  period  of  maintenance  some  one  in  his  em- 
ploy shall  pass  over  the  road  at  least  once  each  week  and  re- 
pair any  washes  or  slips  that  may  occur  in  the  slopes,  see 
that  all  ditches  and  drains  are  in  working  order,  remove  any 
fragments  of  stone  that  may  have  been  loosened  by  the  traf- 
fic, and  resurface  and  reroll  any  portion  of  the  roadway  that 
may  show  signs  of  looseness  or  movement. 

The  statement  will  be  made  that  the  kind  of  work  here 
described  would  be  so  expensive  as  to  preclude  its  general 
adoption,  but  this  assertion  can  be  truthfully  met  by  saying 
that  the  cost  per  mile  of  this  work  will  be  little  if  any 
greater,  and  in  most  instances  actually  less  than  that  now  used 
in  so-called  road  improvements  that  do  not  greatly  improve. 
If  crushed  and  screened  stone  can  not  be  had  to  supply  the  sizes 
above  indicated,  use  sound  stone  of  the  kind  which  the  locality 
affords  and  break  it  by  hand.  In  this  case  a  clean  gravel 
should  be  used  instead  of  spalls  for  filling  the  voids  in  the 
broken  stone.  The  gravel  should  be  screened,  so  as  to 
contain  no  pebbles  exceeding  an  inch  in  diameter;  there 
should  be  no  loam,  and  little  if  any  fine  sand  in  it,  but  plenty 
of  coarse  sand,  grit,  and  small  pebbles.  It  should  not  be  put 
on  the  top  of  the  stone  and  left  to  chance,  but  it  should  be 
incorporated  with  it  and  compacted  by  water  and  pressure. 
If  no  roller  can  be  had  it  must  be  cared  for  and  kept  smooth 
until  compacted  by  the  traffic.  The  word  spalls  as  used  in 


106  COUNTRY   ROADS. 

this  paper  means  small  angular  fragments  of  crystalline 
rock,  not  the  shale,  dirt,  and  rubbish  that  may  be  separated 
from  the  crushed  stone,  and  commonly  called  screenings. 

It  follows  from  what  has  been  said  that  three  essentials 
are  necessary  for  the  construction  of  a  good  macadam  or 
broken  stone  road :  First.  That  the  ground  or  soil  upon 
which  the  metal  is  to  be  placed  shall  be  properly  graded, 
drained,  and  compacted,  so  that  its  condition  and  bearing 
power  shall  remain  constant,  or  as  nearly  so  as  is  practicable. 
Second.  That  the  soil  thus  prepared  shall  be  covered  with  a 
coating  that  shall  be  permeable  to  the  escaping  ground 
water  and  lead  it  to  the  drains,  but  shall  not  be  dissolved  or 
removed  by  it,  and  shall  distribute  the  weight  of  the  traffic 
without  any  internal  movement,  over  sufficient  areas  to 
enable  the  soil  to  carry  it.  Third.  That  a  wearing  surface 
shall  be  placed  upon  the  roadway  so  firmly  compacted  and 
smooth  that  it  will  be  impervious  to  the  rainfall,  that  shall 
not  be  displaced  by  the  hoofs  or  wheels  of  traffic,  and  that 
shall  resist  the  wear  for  a  reasonable  length  of  time.  All  of 
these  conditions  can  be  met  at  reasonable  cost,  providing 
nothing  goes  into  the  metal  that  will  readily  make  a  solution 
with  water,  and  intelligent,  careful  supervision  be  given  to 
the  entire  work. 

There  is  nothing  new  in  this,  for  these  are  the  principles 
enunciated  and  practiced  by  MacAdam  and  Telford  nearly 
one  hundred  years  ago ;  but  the  belief  has  become  general 
that  the  building  of  a  road  consists  in  stirring  up  the  surface 
along  its  length  by  a  process  called  grading,  and  then  cover- 
ing a  streak  of  it  with  broken  stone  and  gravel,  and  that  no 
especial  knowledge  or  skill  are  required  to  do  this.  It  would 
be  as  reasonable  to  expect  to  get  a  good  time-piece  by  buying 
a  watch-case  and  putting  some  wheels  in  it  as  to  obtain  any 
reasonable  return  for  money  thus  expended  in  road  building. 


COUNTRY   KOADS.  107 

We  are  not  suffering  so  much  from  stealing  or  corruption  in 
office  in  these  matters,  as  from  incompetence  and  crass  ig- 
norance. If  the  moneys  now  wasted  could  be  expended  un- 
der honest,  competent  supervision,  a  very  few  years  in  time 
would  show  such  betterments  in  the  condition  of  our  country 
highways  that  any  additional  funds  that  might  be  shown  to 
be  necessary  for  further  improvement  would  be  forthcoming 
without  a  murmur. 

Those  who  officiate  as  engineers  are  not  entirely  at  fault, 
because  ordinances  or  even  statutes  generally  prescribe  not 
only  that  which  is  to  be  done,  but  the  method  of  doing  it, 
and  specifications  must  be  drawn  to  meet  these  requirements 
of  the  ordinance  or  statute.  The  first  essential  toward  bet- 
terment must  be  to  convince  people  that  knowledge  and 
skill  are  necessary  in  road  making.  Neither  lawyers,  mer- 
chants, farmers,  nor  engineers  can  successfully  direct  such 
work  until  after  they  shall  have  acquired  a  knowledge  of 
the  principles  which  should  govern  it,  and  by  experience 
learned  how  to  apply  them. 

The  statutes  pertaining  to  road  making  assume  that  no 
training  or  skill  is  required  to  qualify  any  person  to  direct 
the  work.  That  fallacy  must  be  corrected  before  any  essen- 
tial saving  can  be  effected  from  the  funds  now  being  wasted. 
The  building  and  maintenance  of  roads  in  the  more  densely 
populated  districts  must  be  placed  under  the  direction  of 
engineers  skilled  in  the  work,  owing  no  allegiance  to,  nor 
subject  to  any  disturbance  from  politicians,  before  any  perma- 
manent  betterment  can  be  expected  in  this  matter.  In  the 
smaller  villages  and  rural  districts  the  dissemination  of 
knowledge  upon  the  subject  will  be  useful  but  slow  in  pro- 
ducing results. 

If  a  person  skilled  in  the  construction  and  maintenance 
of  roads  and  streets,  and  in  the  organization  and  direction 


108  COUNTRY   ROADS. 

of  forces  in  executing  public  works,  were  to  equip  and  effici- 
ently employ  in  each  county  such  a  force  as,  with  the  neces- 
sary materials  to  be  used,  would  equal  in  cost  each  year  the 
amounts  levied  and  collected  in  labor  and  money  in  that 
county  for  the  improvement  and  maintenance  of  roads,  ten 
years  would  not  elapse  until  every  highway  in  each  county 
would  have  received  all  the  improvement  necessary  to  make 
it  at  all  times  passable  and  suited  to  the  traffic  which  it  would 
be  required  to  carry.  There  might  be  exceptions,  but  as  a 
rule  this  statement  would  be  true.  We  are  confronted  with 
the  fact,  however,  that  such  a  proceeding  would  not  be  in 
accordance  with  law,  and  when  our  solons  are  asked  for  a 
betterment  of  the  laws,  great  obstacles  are  found  in  the  way. 
The  only  remedies  furnished  by  them  is  in  adding  additional 
burdens  to  tax-payers,  more  offices  to  be  filled  by  incompe- 
tent persons,  and  more  money  to  be  wasted  in  ignorance  or 
knavery.  The  very  muddiness  of  the  subject  is  a  disgrace 
to  the  country,  the  loss  and  waste  is  sufficient  to  pension  all 
the  politicians  in  the  land,  but  betterment  may  come  when 
the  folly  of  submitting  to  existing  conditions  is  apprehended 
by  a  majority  of  the  people. 


• 


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FORM  NO.  DD6 


BERKELEY,  CA  94720 


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